[ { "id": "authors:yq26w-j7a04", "collection": "authors", "collection_id": "yq26w-j7a04", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20210503-115704622", "type": "article", "title": "High-resolution CARMA Observation of Molecular Gas in the North America and Pelican Nebulae", "author": [ { "family_name": "Kong", "given_name": "Shuo", "orcid": "0000-0002-8469-2029", "clpid": "Kong-Shuo" }, { "family_name": "Arce", "given_name": "H\u00e9ctor G.", "orcid": "0000-0001-5653-7817", "clpid": "Arce-H\u00e9ctor-G" }, { "family_name": "Carpenter", "given_name": "John M.", "orcid": "0000-0003-2251-0602", "clpid": "Carpenter-John-M" }, { "family_name": "Bally", "given_name": "John", "orcid": "0000-0001-8135-6612", "clpid": "Bally-John" }, { "family_name": "Ossenkopf-Okada", "given_name": "Volker", "orcid": "0000-0002-8351-3877", "clpid": "Ossenkopf-Okada-Volker" }, { "family_name": "S\u00e1nchez-Monge", "given_name": "\u00c1lvaro", "orcid": "0000-0002-3078-9482", "clpid": "S\u00e1nchez-Monge-\u00c1lvaro" }, { "family_name": "Sargent", "given_name": "Anneila I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Suri", "given_name": "S\u00fcmeyye", "orcid": "0000-0003-0412-8522", "clpid": "Suri-S\u00fcmeyye" }, { "family_name": "McGehee", "given_name": "Peregrine", "orcid": "0000-0003-0948-6716", "clpid": "McGehee-Peregrine-M" }, { "family_name": "Lis", "given_name": "Dariusz C.", "orcid": "0000-0002-0500-4700", "clpid": "Lis-Dariusz-C" }, { "family_name": "Klessen", "given_name": "Ralf S.", "orcid": "0000-0002-0560-3172", "clpid": "Klessen-Ralf-S" }, { "family_name": "Mairs", "given_name": "Steve", "orcid": "0000-0002-6956-0730", "clpid": "Mairs-Steven-T" }, { "family_name": "Zucker", "given_name": "Catherine", "orcid": "0000-0002-2250-730X", "clpid": "Zucker-Catherine" }, { "family_name": "Smith", "given_name": "Rowan J.", "orcid": "0000-0002-0820-1814", "clpid": "Smith-Rowan-J" }, { "family_name": "Nakamura", "given_name": "Fumitaka", "orcid": "0000-0001-5431-2294", "clpid": "Nakamura-Fumikata" }, { "family_name": "Pillai", "given_name": "Thushara G. S.", "orcid": "0000-0003-2133-4862", "clpid": "Pillai-Thushara-G-S" }, { "family_name": "Kauffmann", "given_name": "Jens", "orcid": "0000-0002-5094-6393", "clpid": "Kauffmann-Jens" }, { "family_name": "Zhang", "given_name": "Shaobo", "orcid": "0000-0003-2549-7247", "clpid": "Zhao-Shaobo" } ], "abstract": "In this paper, we present the first results from a CARMA high-resolution \u00b9\u00b2CO(1-0), \u00b9\u00b3CO(1-0), and C\u00b9\u2078O(1-0) molecular line survey of the North America and Pelican (NAP) Nebulae. CARMA observations have been combined with single-dish data from the Purple Mountain 13.7 m telescope, to add short spacings and to produce high-dynamic-range images. We find that the molecular gas is predominantly shaped by the W80 H ii bubble, driven by an O star. Several bright rims noted in the observation are probably remnant molecular clouds, heated and stripped by the massive star. Matching these rims in molecular lines and optical images, we construct a model of the three-dimensional structure of the NAP complex. Two groups of molecular clumps/filaments are on the near side of the bubble: one is being pushed toward us, whereas the other is moving toward the bubble. Another group is on the far side of the bubble, and moving away. The young stellar objects in the Gulf region reside in three different clusters, each hosted by a cloud from one of the three molecular clump groups. Although all gas content in the NAP is impacted by feedback from the central O star, some regions show no signs of star formation, while other areas clearly exhibit star formation activity. Additional molecular gas being carved by feedback includes cometary structures in the Pelican Head region, and the boomerang features at the boundary of the Gulf region. The results show that the NAP complex is an ideal place for the study of feedback effects on star formation.", "doi": "10.3847/1538-3881/abec7d", "issn": "0004-6256", "publisher": "American Astronomical Society", "publication": "Astronomical Journal", "publication_date": "2021-05", "series_number": "5", "volume": "161", "issue": "5", "pages": "Art. No. 229" }, { "id": "authors:wvdg2-73f78", "collection": "authors", "collection_id": "wvdg2-73f78", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190918-100141595", "type": "article", "title": "Uncle Jesse and the seven \"early career\" ladies of the night", "author": [ { "family_name": "Cohen", "given_name": "Judith", "orcid": "0000-0002-8039-4673", "clpid": "Cohen-J-G" }, { "family_name": "Kayser", "given_name": "Susan", "clpid": "Kayser-S" }, { "family_name": "Peterson", "given_name": "A. Victoria", "clpid": "Peterson-A-V" }, { "family_name": "Sargent", "given_name": "Anneila", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Trimble", "given_name": "Virginia", "clpid": "Trimble-V-L" }, { "family_name": "Weistrop", "given_name": "Donna", "clpid": "Weistrop-D" } ], "abstract": "Jesse Leonard Greenstein (1909\u20132002) was apparently a very hard sell when it came to women in astronomy. Early in his autobiography, he wrote of \"Miss Payne, a person of wide culture and astronomical knowledge. The obvious discrimination against her as a woman scientist, worthy of normal academic recognition, exacerbated the stressful life she led. She was unhappy, emotional, in a rivalry with Menzel and Plaskett.\" She (a.k.a. Cecilia Helena Payne, later Gaposchkin) is the only woman with an explicit mention in that memoir, and Greenstein's impression of her left him uncertain whether women belonged in astronomy. In addition, some of us remember him as saying there was no use in educating women through to a Ph.D. because they only get married and quit.", "doi": "10.1119/1.5122880", "issn": "0002-9505", "publisher": "American Association of Physics Teachers", "publication": "American Journal of Physics", "publication_date": "2019-10", "series_number": "10", "volume": "87", "issue": "10", "pages": "778-783" }, { "id": "authors:88paq-tqv83", "collection": "authors", "collection_id": "88paq-tqv83", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190830-123459865", "type": "article", "title": "CARMA-NRO Orion Survey: Core Emergence and Kinematics in the Orion A Cloud", "author": [ { "family_name": "Kong", "given_name": "Shuo", "orcid": "0000-0002-8469-2029", "clpid": "Kong-Shuo" }, { "family_name": "Arce", "given_name": "H\u00e9ctor G.", "orcid": "0000-0001-5653-7817", "clpid": "Arce-H\u00e9ctor-G" }, { "family_name": "Sargent", "given_name": "Anneila I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Mairs", "given_name": "Steve", "orcid": "0000-0002-6956-0730", "clpid": "Mairs-Steven-T" }, { "family_name": "Klessen", "given_name": "Ralf S.", "orcid": "0000-0002-0560-3172", "clpid": "Klessen-Ralf-S" }, { "family_name": "Bally", "given_name": "John", "orcid": "0000-0001-8135-6612", "clpid": "Bally-John" }, { "family_name": "Padoan", "given_name": "Paolo", "orcid": "0000-0002-5055-5800", "clpid": "Padoan-Paolo" }, { "family_name": "Smith", "given_name": "Rowan J.", "orcid": "0000-0002-0820-1814", "clpid": "Smith-Rowan-J" }, { "family_name": "Maureira", "given_name": "Mar\u00eda Jos\u00e9", "clpid": "Maureira-Mar\u00eda-Jos\u00e9" }, { "family_name": "Carpenter", "given_name": "John M.", "orcid": "0000-0003-2251-0602", "clpid": "Carpenter-John-M" }, { "family_name": "Ginsburg", "given_name": "Adam", "orcid": "0000-0001-6431-9633", "clpid": "Ginsburg-Adam" }, { "family_name": "Stutz", "given_name": "Amelia M.", "orcid": "0000-0003-2300-8200", "clpid": "Stutz-Amelia-M" }, { "family_name": "Goldsmith", "given_name": "Paul", "orcid": "0000-0002-6622-8396", "clpid": "Goldsmith-Paul-F" }, { "family_name": "Meingast", "given_name": "Stefan", "clpid": "Meingast-Stefan" }, { "family_name": "McGehee", "given_name": "Peregrine", "orcid": "0000-0003-0948-6716", "clpid": "McGehee-Peregrine-M" }, { "family_name": "S\u00e1nchez-Monge", "given_name": "\u00c1lvaro", "orcid": "0000-0002-3078-9482", "clpid": "S\u00e1nchez-Monge-\u00c1lvaro" }, { "family_name": "Suri", "given_name": "S\u00fcmeyye", "orcid": "0000-0003-0412-8522", "clpid": "Suri-S\u00fcmeyye" }, { "family_name": "Pineda", "given_name": "Jaime E.", "orcid": "0000-0002-3972-1978", "clpid": "Pineda-Jaime-E" }, { "family_name": "Alves", "given_name": "Jo\u00e3o", "clpid": "Alves-Jo\u00e3o" }, { "family_name": "Feddersen", "given_name": "Jesse R.", "orcid": "0000-0003-3810-3323", "clpid": "Feddersen-Jesse-R" }, { "family_name": "Kauffmann", "given_name": "Jens", "clpid": "Kauffmann-Jens" }, { "family_name": "Schilke", "given_name": "Peter", "orcid": "0000-0003-2141-5689", "clpid": "Schilke-Peter" } ], "abstract": "We have investigated the formation and kinematics of submillimeter (submm) continuum cores in the Orion A molecular cloud. A comparison between submm continuum and near-infrared extinction shows a continuum core detection threshold of A_V ~ 5\u201310 mag. The threshold is similar to the star formation extinction threshold of A_V ~ 7 mag proposed by recent work, suggesting a universal star formation extinction threshold among clouds within 500 pc to the Sun. A comparison between the Orion A cloud and a massive infrared dark cloud G28.37+0.07 indicates that Orion A produces more dense gas within the extinction range 15 mag \u227e A V \u227e 60 mag. Using data from the CARMA-NRO Orion Survey, we find that dense cores in the integral-shaped filament (ISF) show subsonic core-to-envelope velocity dispersion that is significantly less than the local envelope line dispersion, similar to what has been found in nearby clouds. Dynamical analysis indicates that the cores are bound to the ISF. An oscillatory core-to-envelope motion is detected along the ISF. Its origin is to be further explored.", "doi": "10.3847/1538-4357/ab311e", "issn": "1538-4357", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal", "publication_date": "2019-09-01", "series_number": "1", "volume": "882", "issue": "1", "pages": "Art. No. 45" }, { "id": "authors:1pz11-k3p78", "collection": "authors", "collection_id": "1pz11-k3p78", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190613-112836662", "type": "article", "title": "The Effect of Binarity on Circumstellar Disk Evolution", "author": [ { "family_name": "Barenfeld", "given_name": "Scott A.", "orcid": "0000-0001-5222-6851", "clpid": "Barenfeld-S-A" }, { "family_name": "Carpenter", "given_name": "John M.", "orcid": "0000-0003-2251-0602", "clpid": "Carpenter-J-M" }, { "family_name": "Sargent", "given_name": "Anneila I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Rizzuto", "given_name": "Aaron C.", "orcid": "0000-0001-9982-1332", "clpid": "Rizzuto-A-C" }, { "family_name": "Kraus", "given_name": "Adam L.", "orcid": "0000-0001-9811-568X", "clpid": "Kraus-A-L" }, { "family_name": "Meshkat", "given_name": "Tiffany", "orcid": "0000-0001-6126-2467", "clpid": "Meshkat-T" }, { "family_name": "Akeson", "given_name": "Rachel L.", "orcid": "0000-0001-9674-1564", "clpid": "Akeson-R-L" }, { "family_name": "Jensen", "given_name": "Eric L. N.", "orcid": "0000-0002-4625-7333", "clpid": "Jensen-E-L-N" }, { "family_name": "Hinkley", "given_name": "Sasha", "orcid": "0000-0001-8074-2562", "clpid": "Hinkley-S" } ], "abstract": "We present new results on how the presence of stellar companions affects disk evolution based on a study of the 5\u201311 Myr old Upper Scorpius OB Association. Of the 50 G0-M3 Upper Sco members with disks in our sample, only seven host a stellar companion within 2'' and brighter than K = 15, compared to 35 of 75 members without disks. This matches a trend seen in the 1\u20132 Myr old Taurus region, where systems with a stellar companion within 40 au have a lower fraction of infrared-identified disks than those without such companions, indicating shorter disk lifetimes in close multiple systems. However, the fractions of disk systems with a stellar companion within 40 au match in Upper Sco and Taurus. Additionally, we see no difference in the millimeter brightnesses of disks in Upper Sco systems with and without companions, in contrast to Taurus where systems with a companion within 300 au are significantly fainter than wider and single systems. These results suggest that the effects of stellar companions on disk lifetimes occur within the first 1\u20132 Myr of disk evolution, after which companions play little further role. By contrast, disks around single stars lose the millimeter-sized dust grains in their outer regions between ages of 1\u20132 Myr and 5\u201311 Myr. The end result of small dust disk sizes and faint millimeter luminosities is the same whether the disk has been truncated by a companion or has evolved through internal processes.", "doi": "10.3847/1538-4357/ab1e50", "issn": "1538-4357", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal", "publication_date": "2019-06-10", "series_number": "1", "volume": "878", "issue": "1", "pages": "Art. No. 45" }, { "id": "authors:3gmce-jfm95", "collection": "authors", "collection_id": "3gmce-jfm95", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180518-145919578", "type": "article", "title": "The CARMA-NRO Orion Survey", "author": [ { "family_name": "Kong", "given_name": "Shuo", "orcid": "0000-0002-8469-2029", "clpid": "Kong-Shuo" }, { "family_name": "Sargent", "given_name": "Anneila I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Lis", "given_name": "Dariusz C.", "orcid": "0000-0002-0500-4700", "clpid": "Lis-D-C" } ], "abstract": "We present the first results from a new, high-resolution ^(12)CO(1\u20130), ^(13)CO(1\u20130), and C^(18)O(1\u20130) molecular-line survey of the Orion A cloud, hereafter referred to as the CARMA-NRO Orion Survey. CARMA observations have been combined with single-dish data from the Nobeyama 45 m telescope to provide extended images at about 0.01 pc resolution, with a dynamic range of approximately 1200 in spatial scale. Here we describe the practical details of the data combination in uv space, including flux scale matching, the conversion of single-dish data to visibilities, and joint deconvolution of single-dish and interferometric data. A \u0394-variance analysis indicates that no artifacts are caused by combining data from the two instruments. Initial analysis of the data cubes, including moment maps, average spectra, channel maps, position\u2013velocity diagrams, excitation temperature, column density, and line ratio maps, provides evidence of complex and interesting structures such as filaments, bipolar outflows, shells, bubbles, and photo-eroded pillars. The implications for star formation processes are profound, and follow-up scientific studies by the CARMA-NRO Orion team are now underway. We plan to make all the data products described here generally accessible; some are already available at https://dataverse.harvard.edu/dataverse/CARMA-NRO-Orion.", "doi": "10.3847/1538-4365/aabafc", "issn": "1538-4365", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal Supplement Series", "publication_date": "2018-06", "series_number": "2", "volume": "236", "issue": "2", "pages": "Art. No. 25" }, { "id": "authors:veccx-hhf86", "collection": "authors", "collection_id": "veccx-hhf86", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180418-093906316", "type": "article", "title": "Rings and gaps in the disc around Elias 24 revealed by ALMA", "author": [ { "family_name": "Dipierro", "given_name": "G.", "clpid": "Dipierro-G" }, { "family_name": "Ricci", "given_name": "L.", "clpid": "Ricci-L" }, { "family_name": "P\u00e9rez", "given_name": "L. M.", "orcid": "0000-0002-1199-9564", "clpid": "P\u00e9rez-L-M" }, { "family_name": "Lodato", "given_name": "G.", "clpid": "Lodato-G" }, { "family_name": "Alexander", "given_name": "R. D.", "clpid": "Alexander-R-D" }, { "family_name": "Laibe", "given_name": "G.", "clpid": "Laibe-G" }, { "family_name": "Andrews", "given_name": "S.", "clpid": "Andrews-S" }, { "family_name": "Carpenter", "given_name": "J. M.", "orcid": "0000-0003-2251-0602", "clpid": "Carpenter-J-M" }, { "family_name": "Chandler", "given_name": "C. J.", "clpid": "Chandler-C-J" }, { "family_name": "Greaves", "given_name": "J. A.", "clpid": "Greaves-J-A" }, { "family_name": "Hall", "given_name": "C.", "clpid": "Hall-C" }, { "family_name": "Henning", "given_name": "T.", "clpid": "Henning-Thomas" }, { "family_name": "Kwon", "given_name": "W.", "clpid": "Kwon-Woojin" }, { "family_name": "Linz", "given_name": "H.", "clpid": "Linz-H" }, { "family_name": "Mundy", "given_name": "L.", "clpid": "Mundy-L-G" }, { "family_name": "Sargent", "given_name": "A.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Tazzari", "given_name": "M.", "clpid": "Tazzari-M" }, { "family_name": "Testi", "given_name": "L.", "orcid": "0000-0003-1859-3070", "clpid": "Testi-L" }, { "family_name": "Wilner", "given_name": "D.", "orcid": "0000-0003-1526-7587", "clpid": "Wilner-D-J" } ], "abstract": "We present Atacama Large Millimeter/sub-millimeter Array (ALMA) Cycle 2 observations of the 1.3-mm dust continuum emission of the protoplanetary disc surrounding the T Tauri star Elias 24 with an angular resolution of \u223c0.2\u2009arcsec (\u223c28\u2009au). The dust continuum emission map reveals a dark ring at a radial distance of 0.47\u2009arcsec (\u223c65\u2009au) from the central star, surrounded by a bright ring at 0.58\u2009arcsec (\u223c81\u2009au). In the outer disc, the radial intensity profile shows two inflection points at 0.71 and 0.87\u2009arcsec (\u223c99 and 121\u2009au, respectively). We perform global three-dimensional smoothed particle hydrodynamic gas/dust simulations of discs hosting a migrating and accreting planet. Combining the dust density maps of small and large grains with three-dimensional radiative transfer calculations, we produce synthetic ALMA observations of a variety of disc models in order to reproduce the gap- and ring-like features observed in Elias 24. We find that the dust emission across the disc is consistent with the presence of an embedded planet with a mass of \u223c0.7\u2009M_J at an orbital radius of \u223c 60\u2009au. Our model suggests that the two inflection points in the radial intensity profile are due to the inward radial motion of large dust grains from the outer disc. The surface brightness map of our disc model provides a reasonable match to the gap- and ring-like structures observed in Elias 24, with an average discrepancy of \u223c5\u2009per\u2009cent of the observed fluxes around the gap region.", "doi": "10.1093/mnras/sty181", "issn": "0035-8711", "publisher": "Royal Astronomical Society", "publication": "Monthly Notices of the Royal Astronomical Society", "publication_date": "2018-04-21", "series_number": "4", "volume": "475", "issue": "4", "pages": "5296-5312" }, { "id": "authors:xpxss-fa247", "collection": "authors", "collection_id": "xpxss-fa247", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20171215-095223826", "type": "article", "title": "Measurement of Circumstellar Disk Sizes in the Upper Scorpius OB Association with ALMA", "author": [ { "family_name": "Barenfeld", "given_name": "Scott A.", "orcid": "0000-0001-5222-6851", "clpid": "Barenfeld-S-A" }, { "family_name": "Carpenter", "given_name": "John M.", "orcid": "0000-0003-2251-0602", "clpid": "Carpenter-J-M" }, { "family_name": "Sargent", "given_name": "Anneila I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Isella", "given_name": "Andrea", "orcid": "0000-0001-8061-2207", "clpid": "Isella-A" }, { "family_name": "Ricci", "given_name": "Luca", "clpid": "Ricci-L" } ], "abstract": "We present detailed modeling of the spatial distributions of gas and dust in 57 circumstellar disks in the Upper Scorpius OB Association observed with ALMA at submillimeter wavelengths. We fit power-law models to the dust surface density and CO J = 3\u20132 surface brightness to measure the radial extent of dust and gas in these disks. We found that these disks are extremely compact: the 25 highest signal-to-noise disks have a median dust outer radius of 21 au, assuming an R^(-1) dust surface density profile. Our lack of CO detections in the majority of our sample is consistent with these small disk sizes assuming the dust and CO share the same spatial distribution. Of seven disks in our sample with well-constrained dust and CO radii, four appear to be more extended in CO, although this may simply be due to the higher optical depth of the CO. Comparison of the Upper Sco results with recent analyses of disks in Taurus, Ophiuchus, and Lupus suggests that the dust disks in Upper Sco may be approximately three times smaller in size than their younger counterparts, although we caution that a more uniform analysis of the data across all regions is needed. We discuss the implications of these results for disk evolution.", "doi": "10.3847/1538-4357/aa989d", "issn": "1538-4357", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal", "publication_date": "2017-12-20", "series_number": "2", "volume": "851", "issue": "2", "pages": "Art. No. 85" }, { "id": "authors:6zqga-jza37", "collection": "authors", "collection_id": "6zqga-jza37", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170825-140948568", "type": "article", "title": "Kwok-Yung Lo", "author": [ { "family_name": "Vanden Bout", "given_name": "Paul A.", "clpid": "Vanden-Bout-P-A" }, { "family_name": "Sargent", "given_name": "Anneila I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" } ], "abstract": "Radio astronomer and physicist Kwok-Yung \"Fred\" Lo was born on 19 October 1947 in Nanjing, China. The third of six sons, he grew up in Hong Kong, where his father had moved his antique business in 1949 in search of better opportunities. Fred came to the US in 1965 to attend MIT, where he earned his BS in 1969 and a PhD in 1974, both in physics. His thesis, titled \"Interstellar microwave radiation and early stellar evolution,\" was supervised by radio astronomer Bernard Burke.", "doi": "10.1063/PT.3.3669", "issn": "0031-9228", "publisher": "American Institute of Physics", "publication": "Physics Today", "publication_date": "2017-08", "series_number": "8", "volume": "70", "issue": "8", "pages": "71" }, { "id": "authors:vbr9y-83c76", "collection": "authors", "collection_id": "vbr9y-83c76", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161212-100218615", "type": "article", "title": "Ringed Structures of the HD 163296 Protoplanetary Disk Revealed by ALMA", "author": [ { "family_name": "Isella", "given_name": "Andrea", "orcid": "0000-0001-8061-2207", "clpid": "Isella-A" }, { "family_name": "Guidi", "given_name": "Greta", "clpid": "Guidi-G" }, { "family_name": "Testi", "given_name": "Leonardo", "orcid": "0000-0003-1859-3070", "clpid": "Testi-L" }, { "family_name": "Liu", "given_name": "Shangfei", "clpid": "Liu-Shangfei" }, { "family_name": "Li", "given_name": "Hui", "orcid": "0000-0003-3556-6568", "clpid": "Li-Hui" }, { "family_name": "Li", "given_name": "Shengtai", "clpid": "Li-Shengtai" }, { "family_name": "Weaver", "given_name": "Erik", "clpid": "Weaver-E" }, { "family_name": "Boehler", "given_name": "Yann", "clpid": "Boehler-Y" }, { "family_name": "Carpenter", "given_name": "John M.", "orcid": "0000-0003-2251-0602", "clpid": "Carpenter-J-M" }, { "family_name": "de Gregorio-Monsalvo", "given_name": "Itziar", "clpid": "de-Gregorio-Monsalvo-I" }, { "family_name": "Manara", "given_name": "Carlo F.", "orcid": "0000-0003-3562-262X", "clpid": "Manara-C-F" }, { "family_name": "Natta", "given_name": "Antonella", "clpid": "Natta-A" }, { "family_name": "P\u00e9rez", "given_name": "Laura M.", "orcid": "0000-0002-1199-9564", "clpid": "P\u00e9rez-L-M" }, { "family_name": "Ricci", "given_name": "Luca", "clpid": "Ricci-L" }, { "family_name": "Sargent", "given_name": "Anneila", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Tazzari", "given_name": "Marco", "clpid": "Tazzari-M" }, { "family_name": "Turner", "given_name": "Neal", "orcid": "0000-0001-8292-1943", "clpid": "Turner-N-J" } ], "abstract": "We present Atacama Large Millimeter and Submillimeter Array observations of the protoplanetary disk around the Herbig Ae star HD 163296 that trace the spatial distribution of millimeter-sized particles and cold molecular gas on spatial scales as small as 25 astronomical units (A.U.). The image of the disk recorded in the 1.3 mm continuum emission reveals three dark concentric rings that indicate the presence of dust depleted gaps at about 60, 100, and 160 A.U. from the central star. The maps of the ^(12)CO, ^(13)CO, and C^(18)O J=2\u22121 emission do not show such structures but reveal a change in the slope of the radial intensity profile across the positions of the dark rings in the continuum image. By comparing the observations with theoretical models for the disk emission, we find that the density of CO molecules is reduced inside the middle and outer dust gaps. However, in the inner ring there is no evidence of CO depletion. From the measurements of the dust and gas densities, we deduce that the gas-to-dust ratio varies across the disk and, in particular, it increases by at least a factor 5 within the inner dust gap compared to adjacent regions of the disk. The depletion of both dust and gas suggests that the middle and outer rings could be due to the gravitational torque exerted by two Saturn-mass planets orbiting at 100 and 160 A.U. from the star. On the other hand, the inner dust gap could result from dust accumulation at the edge of a magnetorotational instability dead zone, or from dust opacity variations at the edge of the CO frost line. Observations of the dust emission at higher angular resolution and of molecules that probe dense gas are required to establish more precisely the origins of the dark rings observed in the HD 163296 disk.", "doi": "10.1103/PhysRevLett.117.251101", "issn": "0031-9007", "publisher": "American Physical Society", "publication": "Physical Review Letters", "publication_date": "2016-12-16", "series_number": "25", "volume": "117", "issue": "25", "pages": "Art. No. 251101" }, { "id": "authors:8cwsx-n3k09", "collection": "authors", "collection_id": "8cwsx-n3k09", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161010-144112510", "type": "article", "title": "Spiral density waves in a young protoplanetary disk", "author": [ { "family_name": "P\u00e9rez", "given_name": "Laura M.", "orcid": "0000-0002-1199-9564", "clpid": "P\u00e9rez-L-M" }, { "family_name": "Carpenter", "given_name": "John M.", "orcid": "0000-0003-2251-0602", "clpid": "Carpenter-J-M" }, { "family_name": "Andrews", "given_name": "Sean M.", "orcid": "0000-0003-2253-2270", "clpid": "Andrews-S-M" }, { "family_name": "Ricci", "given_name": "Luca", "clpid": "Ricci-L" }, { "family_name": "Isella", "given_name": "Andrea", "orcid": "0000-0001-8061-2207", "clpid": "Isella-A" }, { "family_name": "Linz", "given_name": "Hendrik", "clpid": "Linz-H" }, { "family_name": "Sargent", "given_name": "Anneila I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Wilner", "given_name": "David J.", "orcid": "0000-0003-1526-7587", "clpid": "Wilner-D-J" }, { "family_name": "Henning", "given_name": "Thomas", "clpid": "Henning-Thomas" }, { "family_name": "Deller", "given_name": "Adam T.", "orcid": "0000-0001-9434-3837", "clpid": "Deller-A-T" }, { "family_name": "Chandler", "given_name": "Claire J.", "clpid": "Chandler-C-J" }, { "family_name": "Dullemond", "given_name": "Cornelis P.", "clpid": "Dullemond-C-P" }, { "family_name": "Lazio", "given_name": "Joseph", "clpid": "Lazio-J-W" }, { "family_name": "Menten", "given_name": "Karl M.", "orcid": "0000-0001-6459-0669", "clpid": "Menten-K-M" }, { "family_name": "Corder", "given_name": "Stuartt A.", "clpid": "Corder-S-A" }, { "family_name": "Storm", "given_name": "Shaye", "orcid": "0000-0001-9401-1357", "clpid": "Storm-S" }, { "family_name": "Testi", "given_name": "Leonardo", "orcid": "0000-0003-1859-3070", "clpid": "Testi-L" }, { "family_name": "Tazzari", "given_name": "Marco", "clpid": "Tazzari-M" }, { "family_name": "Kwon", "given_name": "Woojin", "clpid": "Kwon-Woojin" }, { "family_name": "Calvet", "given_name": "Nuria", "orcid": "0000-0002-3950-5386", "clpid": "Calvet-Nuria" }, { "family_name": "Greaves", "given_name": "Jane S.", "orcid": "0000-0002-3133-413X", "clpid": "Greaves-J-S" }, { "family_name": "Harris", "given_name": "Robert J.", "clpid": "Harris-R-J" }, { "family_name": "Mundy", "given_name": "Lee G.", "clpid": "Mundy-L-G" } ], "abstract": "Gravitational forces are expected to excite spiral density waves in protoplanetary disks, disks of gas and dust orbiting young stars. However, previous observations that showed spiral structure were not able to probe disk midplanes, where most of the mass is concentrated and where planet formation takes place. Using the Atacama Large Millimeter/submillimeter Array, we detected a pair of trailing symmetric spiral arms in the protoplanetary disk surrounding the young star Elias 2-27. The arms extend to the disk outer regions and can be traced down to the midplane. These millimeter-wave observations also reveal an emission gap closer to the star than the spiral arms. We argue that the observed spirals trace shocks of spiral density waves in the midplane of this young disk.", "doi": "10.1126/science.aaf8296", "issn": "0036-8075", "publisher": "American Association for the Advancement of Science", "publication": "Science", "publication_date": "2016-09-30", "series_number": "6307", "volume": "353", "issue": "6307", "pages": "1519-1521" }, { "id": "authors:y2980-07d89", "collection": "authors", "collection_id": "y2980-07d89", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160519-131754421", "type": "article", "title": "Multiwavelength analysis for interferometric (sub-)mm observations of protoplanetary disks: Radial constraints on the dust properties of protoplanetary disks", "author": [ { "family_name": "Tazzari", "given_name": "M.", "clpid": "Tazzari-M" }, { "family_name": "Testi", "given_name": "L.", "orcid": "0000-0003-1859-3070", "clpid": "Testi-L" }, { "family_name": "Ercolano", "given_name": "B.", "clpid": "Ercolano-B" }, { "family_name": "Natta", "given_name": "A.", "clpid": "Natta-A" }, { "family_name": "Isella", "given_name": "A.", "orcid": "0000-0001-8061-2207", "clpid": "Isella-A" }, { "family_name": "Chandler", "given_name": "C. J.", "clpid": "Chandler-C-J" }, { "family_name": "P\u00e9rez", "given_name": "L. M.", "orcid": "0000-0002-1199-9564", "clpid": "P\u00e9rez-L-M" }, { "family_name": "Andrews", "given_name": "S.", "clpid": "Andrews-S" }, { "family_name": "Wilner", "given_name": "D. J.", "orcid": "0000-0003-1526-7587", "clpid": "Wilner-D-J" }, { "family_name": "Ricci", "given_name": "L.", "clpid": "Ricci-L" }, { "family_name": "Henning", "given_name": "T.", "clpid": "Henning-Thomas" }, { "family_name": "Linz", "given_name": "H.", "clpid": "Linz-H" }, { "family_name": "Kwon", "given_name": "W.", "clpid": "Kwon-Woojin" }, { "family_name": "Corder", "given_name": "S. A.", "clpid": "Corder-S" }, { "family_name": "Dullemond", "given_name": "C. P.", "clpid": "Dullemond-C-P" }, { "family_name": "Carpenter", "given_name": "J. M.", "orcid": "0000-0003-2251-0602", "clpid": "Carpenter-J-M" }, { "family_name": "Sargent", "given_name": "A. I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Mundy", "given_name": "L.", "clpid": "Mundy-L-G" }, { "family_name": "Storm", "given_name": "S.", "orcid": "0000-0001-9401-1357", "clpid": "Storm-S" }, { "family_name": "Calvet", "given_name": "N.", "orcid": "0000-0002-3950-5386", "clpid": "Calvet-Nuria" }, { "family_name": "Greaves", "given_name": "J. A.", "clpid": "Greaves-J-A" }, { "family_name": "Lazio", "given_name": "J.", "clpid": "Lazio-T-J-W" }, { "family_name": "Deller", "given_name": "A. T.", "orcid": "0000-0001-9434-3837", "clpid": "Deller-A-T" } ], "abstract": "Context. The growth of dust grains from sub-\u03bcm to mm and cm sizes is the first step towards the formation of planetesimals. Theoretical models of grain growth predict that dust properties change as a function of disk radius, mass, age, and other physical conditions. High angular resolution observations at several (sub-)mm wavelengths constitute the ideal tool with which to directly probe the bulk of dust grains and to investigate the radial distribution of their properties.\n\nAims. We lay down the methodology for a multiwavelength analysis of (sub-)mm and cm continuum interferometric observations to self-consistently constrain the disk structure and the radial variation of the dust properties. The computational architecture is massively parallel and highly modular.\n\nMethods. The analysis is based on the simultaneous fit in the uv-plane of observations at several wavelengths with a model for the disk thermal emission and for the dust opacity. The observed flux density at the different wavelengths is fitted by posing constraints on the disk structure and on the radial variation of the grain size distribution.\n\nResults. We apply the analysis to observations of three protoplanetary disks (AS 209, FT Tau, DR Tau) for which a combination of spatially resolved observations in the range ~0.88 mm to ~10 mm is available from SMA, CARMA, and VLA. In these disks we find evidence of a decrease in the maximum dust grain size, a_(max), with radius. We derive large a_(max) values up to 1\u2009cm in the inner disk 15 AU \u2264 R \u2264 30 AU and smaller grains with a_(max) ~ 1 mm in the outer disk (R \u2273 80 AU). Our analysis of the AS 209 protoplanetary disk confirms previous literature results showing amax decreasing with radius.\n\nConclusions. Theoretical studies of planetary formation through grain growth are plagued by the lack of direct information on the radial distribution of the dust grain size. In this paper we develop a multiwavelength analysis that will allow this missing quantity to be constrained for statistically relevant samples of disks and to investigate possible correlations with disk or stellar parameters.", "doi": "10.1051/0004-6361/201527423", "issn": "0004-6361", "publisher": "EDP Sciences", "publication": "Astronomy and Astrophysics", "publication_date": "2016-04", "volume": "588", "pages": "Art. No. A53" }, { "id": "authors:vnhxw-86m10", "collection": "authors", "collection_id": "vnhxw-86m10", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160519-122854806", "type": "article", "title": "Dust properties across the CO snowline in the HD 163296 disk from ALMA and VLA observations", "author": [ { "family_name": "Guidi", "given_name": "G.", "clpid": "Guidi-G-M" }, { "family_name": "Tazzari", "given_name": "M.", "clpid": "Tazzari-M" }, { "family_name": "Testi", "given_name": "L.", "orcid": "0000-0003-1859-3070", "clpid": "Testi-L" }, { "family_name": "de Gregorio-Monsalvo", "given_name": "I.", "clpid": "de-Gregorio-Monsalvo-I" }, { "family_name": "Chandler", "given_name": "C. J.", "clpid": "Chandler-C-J" }, { "family_name": "Perez", "given_name": "L.", "orcid": "0000-0002-1199-9564", "clpid": "P\u00e9rez-L-M" }, { "family_name": "Isella", "given_name": "A.", "orcid": "0000-0001-8061-2207", "clpid": "Isella-A" }, { "family_name": "Natta", "given_name": "A.", "clpid": "Natta-A" }, { "family_name": "Ortolani", "given_name": "S.", "clpid": "Ortolani-S" }, { "family_name": "Henning", "given_name": "Th.", "clpid": "Henning-Thomas" }, { "family_name": "Corder", "given_name": "S.", "clpid": "Corder-S-A" }, { "family_name": "Linz", "given_name": "H.", "clpid": "Linz-H" }, { "family_name": "Andrews", "given_name": "S.", "clpid": "Andrews-S" }, { "family_name": "Wilner", "given_name": "D.", "orcid": "0000-0003-1526-7587", "clpid": "Wilner-D-J" }, { "family_name": "Ricci", "given_name": "L.", "clpid": "Ricci-L" }, { "family_name": "Carpenter", "given_name": "J.", "orcid": "0000-0003-2251-0602", "clpid": "Carpenter-J-M" }, { "family_name": "Sargent", "given_name": "A.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Mundy", "given_name": "L.", "clpid": "Mundy-L-G" }, { "family_name": "Storm", "given_name": "S.", "orcid": "0000-0001-9401-1357", "clpid": "Storm-S" }, { "family_name": "Calvet", "given_name": "N.", "orcid": "0000-0002-3950-5386", "clpid": "Calvet-Nuria" }, { "family_name": "Dullemond", "given_name": "C.", "clpid": "Dullemond-C-P" }, { "family_name": "Greaves", "given_name": "J.", "orcid": "0000-0002-3133-413X", "clpid": "Greaves-J-S" }, { "family_name": "Lazio", "given_name": "J.", "clpid": "Lazio-T-J-W" }, { "family_name": "Deller", "given_name": "A.", "orcid": "0000-0001-9434-3837", "clpid": "Deller-A-T" }, { "family_name": "Kwon", "given_name": "W.", "clpid": "Kwon-Woojin" } ], "abstract": "Context. To characterize the mechanisms of planet formation it is crucial to investigate the properties and evolution of protoplanetary disks around young stars, where the initial conditions for the growth of planets are set. The high spatial resolution of Atacama Large Millimeter/submillimeter Array (ALMA) and Karl G. Jansky Very Large Array (VLA) observations now allows the study of radial variations of dust properties in nearby resolved disks and the investigation of the early stages of grain growth in disk midplanes.\n\nAims. Our goal is to study grain growth in the well-studied disk of the young, intermediate-mass star HD 163296 where dust processing has already been observed and to look for evidence of growth by ice condensation across the CO snowline, which has already been identified in this disk with ALMA.\n\nMethods. Under the hypothesis of optically thin emission, we compare images at different wavelengths from ALMA and VLA to measure the opacity spectral index across the disk and thus the maximum grain size. We also use a Bayesian tool based on a two-layer disk model to fit the observations and constrain the dust surface density.\n\nResults. The measurements of the opacity spectral index indicate the presence of large grains and pebbles (\u22651 cm) in the inner regions of the disk (inside ~50 AU) and smaller grains, consistent with ISM sizes, in the outer disk (beyond 150 AU). Re-analyzing ALMA Band 7 science verification data, we find (radially) unresolved excess continuum emission centered near the location of the CO snowline at ~90 AU.\n\nConclusions. Our analysis suggests a grain size distribution consistent with an enhanced production of large grains at the CO snowline and consequent transport to the inner regions. Our results combined with the excess in infrared scattered light suggests there is a structure at 90 AU involving the whole vertical extent of the disk. This could be evidence of small scale processing of dust at the CO snowline.", "doi": "10.1051/0004-6361/201527516", "issn": "0004-6361", "publisher": "EDP Sciences", "publication": "Astronomy & Astrophysics", "publication_date": "2016-04", "volume": "588", "pages": "Art. No. A112" }, { "id": "authors:ga9vk-3zz70", "collection": "authors", "collection_id": "ga9vk-3zz70", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200131-132810636", "type": "article", "title": "Grain Growth in the Circumstellar Disks of the Young Stars CY Tau and DoAr 25", "author": [ { "family_name": "P\u00e9rez", "given_name": "Laura M.", "orcid": "0000-0002-1199-9564", "clpid": "P\u00e9rez-L-M" }, { "family_name": "Chandler", "given_name": "Claire J.", "clpid": "Chandler-C-J" }, { "family_name": "Isella", "given_name": "Andrea", "orcid": "0000-0001-8061-2207", "clpid": "Isella-A" }, { "family_name": "Carpenter", "given_name": "John M.", "orcid": "0000-0003-2251-0602", "clpid": "Carpenter-J-M" }, { "family_name": "Andrews", "given_name": "Sean M.", "orcid": "0000-0003-2253-2270", "clpid": "Andrews-S-M" }, { "family_name": "Calvet", "given_name": "Nuria", "orcid": "0000-0002-3950-5386", "clpid": "Calvet-Nuria" }, { "family_name": "Corder", "given_name": "Stuartt A.", "clpid": "Corder-S-A" }, { "family_name": "Deller", "given_name": "Adam T.", "orcid": "0000-0001-9434-3837", "clpid": "Deller-A-T" }, { "family_name": "Dullemond", "given_name": "Cornelis P.", "clpid": "Dullemond-C-P" }, { "family_name": "Greaves", "given_name": "Jane S.", "orcid": "0000-0002-3133-413X", "clpid": "Greaves-J-S" }, { "family_name": "Harris", "given_name": "Robert J.", "clpid": "Harris-R-J" }, { "family_name": "Henning", "given_name": "Thomas", "clpid": "Henning-Thomas" }, { "family_name": "Kwon", "given_name": "Woojin", "clpid": "Kwon-Woojin" }, { "family_name": "Lazio", "given_name": "Joseph", "clpid": "Lazio-T-J-W" }, { "family_name": "Linz", "given_name": "Hendrik", "clpid": "Linz-H" }, { "family_name": "Mundy", "given_name": "Lee G.", "clpid": "Mundy-L-G" }, { "family_name": "Ricci", "given_name": "Luca", "clpid": "Ricci-L" }, { "family_name": "Sargent", "given_name": "Anneila I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Storm", "given_name": "Shaye", "orcid": "0000-0001-9401-1357", "clpid": "Storm-S" }, { "family_name": "Tazzari", "given_name": "Marco", "clpid": "Tazzari-M" }, { "family_name": "Testi", "given_name": "Leonardo", "orcid": "0000-0003-1859-3070", "clpid": "Testi-L" }, { "family_name": "Wilner", "given_name": "David J.", "orcid": "0000-0003-1526-7587", "clpid": "Wilner-D-J" } ], "abstract": "We present new results from the Disks@EVLA program for two young stars: CY Tau and DoAr 25. We trace continuum emission arising from their circusmtellar disks from spatially resolved observations, down to tens of AU scales, at \u03bb = 0.9, 2.8, 8.0, 9.8 mm for DoAr 25 and at \u03bb = 1.3, 2.8, 7.1 mm for CY Tau. Additionally, we constrain the amount of emission whose origin is different from thermal dust emission from 5 cm observations. Directly from interferometric data, we find that observations at 7 mm and 1 cm trace emission from a compact disk while millimeter-wave observations trace an extended disk structure. From a physical disk model, where we characterize the disk structure of CY Tau and DoAr 25 at wavelengths shorter than 5 cm, we find that (1) dust continuum emission is optically thin at the observed wavelengths and over the spatial scales studied, (2) a constant value of the dust opacity is not warranted by our observations, and (3) a high-significance radial gradient of the dust opacity spectral index, \u03b2, is consistent with the observed dust emission in both disks, with low-\u03b2 in the inner disk and high-\u03b2 in the outer disk. Assuming that changes in dust properties arise solely due to changes in the maximum particle size (a_(max)), we constrain radial variations of a_(max) in both disks, from cm-sized particles in the inner disk (R < 40 AU) to millimeter sizes in the outer disk (R > 80 AU). These observational constraints agree with theoretical predictions of the radial-drift barrier, however, fragmentation of dust grains could explain our a_(max)(R) constraints if these disks have lower turbulence and/or if dust can survive high-velocity collisions.", "doi": "10.1088/0004-637x/813/1/41", "issn": "1538-4357", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal", "publication_date": "2015-11-01", "series_number": "1", "volume": "813", "issue": "1", "pages": "Art. No. 41" }, { "id": "authors:mtc5e-caf47", "collection": "authors", "collection_id": "mtc5e-caf47", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20131203-090250079", "type": "article", "title": "The Keck Interferometer", "author": [ { "family_name": "Colavita", "given_name": "M. M.", "clpid": "Colavita-M-M" }, { "family_name": "Akeson", "given_name": "R. L.", "orcid": "0000-0001-9674-1564", "clpid": "Akeson-R-L" }, { "family_name": "Millan-Gabet", "given_name": "R.", "orcid": "0000-0003-0447-5866", "clpid": "Millan-Gabet-R" }, { "family_name": "Abajian", "given_name": "M.", "clpid": "Abajian-M" }, { "family_name": "Beichman", "given_name": "C. A.", "orcid": "0000-0002-5627-5471", "clpid": "Beichman-C-A" }, { "family_name": "Boden", "given_name": "A. F.", "clpid": "Boden-A-F" }, { "family_name": "Felizardo", "given_name": "C.", "clpid": "Felizardo-C" }, { "family_name": "Henderson", "given_name": "H.", "clpid": "Henderson-H" }, { "family_name": "Herstein", "given_name": "J. S.", "clpid": "Herstein-J-S" }, { "family_name": "Koresko", "given_name": "C. D.", "clpid": "Koresko-C-D" }, { "family_name": "Papin", "given_name": "M.", "clpid": "Papin-M" }, { "family_name": "Sargent", "given_name": "A.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" } ], "abstract": "The Keck Interferometer (KI) combined the two 10 m W. M. Keck Observatory telescopes on Mauna Kea, Hawaii, as a long-baseline near- and mid-infrared interferometer. Funded by NASA, it operated from 2001 until 2012. KI used adaptive optics on the two Keck telescopes to correct the individual wavefronts, as well as active fringe tracking in all modes for path-length control, including the implementation of cophasing to provide long coherent integration times. KI implemented high sensitivity fringe-visibility measurements at H (1.6 \u03bcm), K (2.2 \u03bcm), and L (3.8 \u03bcm) bands, and nulling measurements at N band (10 \u03bcm), which were used to address a broad range of science topics. Supporting these capabilities was an extensive interferometer infrastructure and unique instrumentation, including some additional functionality added as part of the NSF-funded ASTRA program. This paper provides an overview of the instrument architecture and some of the key design and implementation decisions, as well as a description of all of the key elements and their configuration at the end of the project. The objective is to provide a view of KI as an integrated system, and to provide adequate technical detail to assess the implementation. Included is a discussion of the operational aspects of the system, as well as of the achieved system performance. Finally, details on V^2 calibration in the presence of detector nonlinearities as applied in the data pipeline are provided.", "doi": "10.1086/673475", "issn": "0004-6280", "publisher": "Astronomical Society of the Pacific", "publication": "Publications of the Astronomical Society of the Pacific", "publication_date": "2013-10", "series_number": "932", "volume": "125", "issue": "932", "pages": "1226-1264" }, { "id": "authors:dzxse-tpv69", "collection": "authors", "collection_id": "dzxse-tpv69", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20130924-110532119", "type": "article", "title": "CARMA observations of protostellar outflows in NGC 1333", "author": [ { "family_name": "Plunkett", "given_name": "Adele L.", "clpid": "Plunkett-A-L" }, { "family_name": "Arce", "given_name": "H\u00e9ctor G.", "orcid": "0000-0001-5653-7817", "clpid": "Arce-H-G" }, { "family_name": "Corder", "given_name": "Stuartt A.", "clpid": "Corder-S-A" }, { "family_name": "Mardones", "given_name": "Diego", "clpid": "Mardones-D" }, { "family_name": "Sargent", "given_name": "Anneila I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Schnee", "given_name": "Scott L.", "clpid": "Schnee-S-L" } ], "abstract": "We present observations of outflows in the star-forming region NGC 1333 using the Combined Array for Research in Millimeter-Wave Astronomy (CARMA). We combined the ^(12)CO and ^(13)CO (1-0) CARMA mosaics with data from the 14 m Five College Radio Astronomy Observatory to probe the central, most dense, and active region of this protostellar cluster at scales from 5\" to 7' (or 1000 AU to 0.5 pc at a distance of 235 pc). We map and identify ^(12)CO outflows, and along with ^(13)CO data we estimate their mass, momentum, and energy. Within the 7' \u00d7 7' map, the 5\" resolution allows for a detailed study of morphology and kinematics of outflows and outflow candidates, some of which were previously confused with other outflow emission in the region. In total, we identify 22 outflow lobes, as well as 9 dense circumstellar envelopes marked by continuum emission, of which 6 drive outflows. We calculate a total outflow mass, momentum, and energy within the mapped region of 6 M_\u2609, 19 M_\u2609 km s^(\u20131), and 7 \u00d7 10^(44) erg, respectively. Within this same region, we compare outflow kinematics with turbulence and gravitational energy, and we suggest that outflows are likely important agents for the maintenance of turbulence in this region. In the earliest stages of star formation, outflows do not yet contribute enough energy to totally disrupt the clustered region where most star formation is happening, but have the potential to do so as the protostellar sources evolve. Our results can be used to constrain outflow properties, such as outflow strength, in numerical simulations of outflow-driven turbulence in clusters.", "doi": "10.1088/0004-637X/774/1/22", "issn": "0004-637X", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal", "publication_date": "2013-09-01", "series_number": "1", "volume": "774", "issue": "1", "pages": "Art. No. 22" }, { "id": "authors:kbgq2-v7685", "collection": "authors", "collection_id": "kbgq2-v7685", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20181211-091513662", "type": "book_section", "title": "TW Hydrae: multi-wavelength interferometry of a transition disk", "book_title": "Exploring the Formation and Evolution of Planetary Systems", "author": [ { "family_name": "Menu", "given_name": "J.", "clpid": "Menu-J" }, { "family_name": "van Boekel", "given_name": "R.", "clpid": "van-Boekel-R" }, { "family_name": "Henning", "given_name": "T.", "clpid": "Henning-T" }, { "family_name": "Benisty", "given_name": "M.", "orcid": "0000-0002-7695-7605", "clpid": "Benisty-M" }, { "family_name": "Chandler", "given_name": "C. J.", "clpid": "Chandler-C-J" }, { "family_name": "Linz", "given_name": "H.", "clpid": "Linz-H" }, { "family_name": "Waelkens", "given_name": "C.", "clpid": "Waelkens-C" }, { "family_name": "Andrews", "given_name": "S. M.", "orcid": "0000-0003-2253-2270", "clpid": "Andrews-S-M" }, { "family_name": "Calvet", "given_name": "N.", "orcid": "0000-0002-3950-5386", "clpid": "Calvet-Nuria" }, { "family_name": "Carpenter", "given_name": "J. M.", "orcid": "0000-0003-2251-0602", "clpid": "Carpenter-J-M" }, { "family_name": "Corder", "given_name": "S. A.", "clpid": "Corder-S" }, { "family_name": "Deller", "given_name": "A. T.", "orcid": "0000-0001-9434-3837", "clpid": "Deller-A-T" }, { "family_name": "Dullemond", "given_name": "C. P.", "clpid": "Dullemond-C-P" }, { "family_name": "Greaves", "given_name": "J. S.", "orcid": "0000-0002-3133-413X", "clpid": "Greaves-J-S" }, { "family_name": "Harris", "given_name": "R. J.", "clpid": "Harris-R-J" }, { "family_name": "Isella", "given_name": "A.", "orcid": "0000-0001-8061-2207", "clpid": "Isella-A" }, { "family_name": "Kwon", "given_name": "W.", "clpid": "Kwon-Woojin" }, { "family_name": "Lazio", "given_name": "J.", "clpid": "Lazio-J" }, { "family_name": "Mundy", "given_name": "L. G.", "clpid": "Mundy-L-G" }, { "family_name": "P\u00e9rez", "given_name": "L. M.", "orcid": "0000-0002-1199-9564", "clpid": "P\u00e9rez-L-M" }, { "family_name": "Ricci", "given_name": "L.", "clpid": "Ricci-L" }, { "family_name": "Sargent", "given_name": "A. I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Storm", "given_name": "S.", "orcid": "0000-0001-9401-1357", "clpid": "Storm-S" }, { "family_name": "Testi", "given_name": "L.", "orcid": "0000-0003-1859-3070", "clpid": "Testi-L" }, { "family_name": "Wilner", "given_name": "D. J.", "orcid": "0000-0003-1526-7587", "clpid": "Wilner-D-J" } ], "contributor": [ { "family_name": "Booth", "given_name": "Mark", "clpid": "Booth-M" }, { "family_name": "Matthews", "given_name": "Brenda C.", "clpid": "Matthews-B-C" }, { "family_name": "Graham", "given_name": "James R.", "clpid": "Graham-J-R" } ], "abstract": "For over a decade, the structure of the inner \"hole\" in the transition disk around TW Hydrae has been a subject of debate. To probe the innermost regions of the protoplanetary disk, observations at the highest possible spatial resolution are required. We present new interferometric data of TW Hya from near-infrared to millimeter wavelengths. We confront existing models of the disk structure with the complete data set and develop a new, detailed radiative-transfer model. This model is characterized by: 1) a spatial separation of the largest grains from the small disk grains; and 2) a smooth inner rim structure, rather than a sharp disk edge.", "doi": "10.1017/s1743921313008016", "isbn": "9781107045200", "publisher": "Cambridge University Press", "place_of_publication": "Cambridge", "publication_date": "2013-06", "pages": "104-108" }, { "id": "authors:x1bzr-4g934", "collection": "authors", "collection_id": "x1bzr-4g934", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20110318-145129310", "type": "article", "title": "Radial Structure in the TW Hya Circumstellar Disk", "author": [ { "family_name": "Akeson", "given_name": "R. L.", "orcid": "0000-0001-9674-1564", "clpid": "Akeson-R-L" }, { "family_name": "Millan-Gabet", "given_name": "R.", "orcid": "0000-0003-0447-5866", "clpid": "Millan-Gabet-R" }, { "family_name": "Ciardi", "given_name": "D. R.", "orcid": "0000-0002-5741-3047", "clpid": "Ciardi-D-R" }, { "family_name": "Boden", "given_name": "A. F.", "clpid": "Boden-A-F" }, { "family_name": "Sargent", "given_name": "A. I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Monnier", "given_name": "J. D.", "orcid": "0000-0002-3380-3307", "clpid": "Monnier-J-D" }, { "family_name": "McAlister", "given_name": "H.", "clpid": "McAlister-H" }, { "family_name": "ten Brummelaar", "given_name": "T.", "orcid": "0000-0002-0114-7915", "clpid": "ten-Brummelaar-Theo-A" }, { "family_name": "Sturmann", "given_name": "J.", "clpid": "Sturmann-J" }, { "family_name": "Sturmann", "given_name": "L.", "clpid": "Sturmann-L" }, { "family_name": "Turner", "given_name": "N.", "clpid": "Turner-N" } ], "abstract": "We present new near-infrared interferometric data from the CHARA array and the Keck Interferometer on the circumstellar disk of the young star, TW Hya, a proposed \"transition disk.\" We use these data, as well as previously published, spatially resolved data at 10 \u03bcm and 7 mm, to constrain disk models based on a standard flared disk structure. We find that we can match the interferometry data sets and the overall spectral energy distribution with a three-component model, which combines elements at spatial scales proposed by previous studies: optically thin, emission nearest the star, an inner optically thick ring of emission at roughly 0.5 AU followed by an opacity gap and, finally, an outer optically thick disk starting at ~4 AU. The model demonstrates that the constraints imposed by the spatially resolved data can be met with a physically plausible disk but this requires a disk containing not only an inner gap in the optically thick disk as previously suggested, but also a gap between the inner and outer optically thick disks. Our model is consistent with the suggestion by Calvet et al. of a planet with an orbital radius of a few AU. We discuss the implications of an opacity gap within the optically thick disk.", "doi": "10.1088/0004-637X/728/2/96", "issn": "0004-637X", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal", "publication_date": "2011-02-20", "series_number": "2", "volume": "728", "issue": "2", "pages": "Art. No. 96" }, { "id": "authors:384rt-gnj07", "collection": "authors", "collection_id": "384rt-gnj07", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20110105-153920945", "type": "article", "title": "The Spitzer c2d Survey of Weak-line T Tauri Stars. III. The Transition from Primordial Disks to Debris Disks", "author": [ { "family_name": "Wahhaj", "given_name": "Zahed", "orcid": "0000-0001-8269-324X", "clpid": "Wahhaj-Z" }, { "family_name": "Cieza", "given_name": "Lucas", "orcid": "0000-0002-2828-1153", "clpid": "Cieza-L-A" }, { "family_name": "Koerner", "given_name": "David W.", "clpid": "Koerner-D-W" }, { "family_name": "Stapelfeldt", "given_name": "Karl R.", "orcid": "0000-0002-2805-7338", "clpid": "Stapelfeldt-K-R" }, { "family_name": "Padgett", "given_name": "Deborah L.", "orcid": "0000-0001-5334-5107", "clpid": "Padgett-D-L" }, { "family_name": "Case", "given_name": "April", "clpid": "Case-A" }, { "family_name": "Keller", "given_name": "James R.", "clpid": "Keller-J-R" }, { "family_name": "Mer\u00edn", "given_name": "Bruno", "clpid": "Mer\u00edn-B" }, { "family_name": "Evans", "given_name": "Neal J., II", "orcid": "0000-0001-5175-1777", "clpid": "Evans-N-J-II" }, { "family_name": "Harvey", "given_name": "Paul", "clpid": "Harvey-P-M" }, { "family_name": "Sargent", "given_name": "Anneila", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "van Dishoeck", "given_name": "Ewine F.", "orcid": "0000-0001-7591-1907", "clpid": "van-Dishoeck-E-F" }, { "family_name": "Allen", "given_name": "Lori", "clpid": "Allen-L-E" }, { "family_name": "Blake", "given_name": "Geoff", "orcid": "0000-0003-0787-1610", "clpid": "Blake-G-A" }, { "family_name": "Brooke", "given_name": "Tim", "clpid": "Brooke-T-Y" }, { "family_name": "Chapman", "given_name": "Nicholas", "clpid": "Chapman-N-L" }, { "family_name": "Mundy", "given_name": "Lee", "clpid": "Mundy-L-G" }, { "family_name": "Myers", "given_name": "Philip C.", "clpid": "Myers-P-C" } ], "abstract": "We present 3.6 to 70 \u03bcm Spitzer photometry of 154 weak-line T Tauri stars (WTTSs) in the Chamaeleon, Lupus, Ophiuchus, and Taurus star formation regions, all of which are within 200 pc of the Sun. For a comparative study, we also include 33 classical T Tauri stars which are located in the same star-forming regions. Spitzer sensitivities allow us to robustly detect the photosphere in the IRAC bands (3.6 to 8 \u03bcm) and the 24 \u03bcm MIPS band. In the 70 \u03bcm MIPS band, we are able to detect dust emission brighter than roughly 40 times the photosphere. These observations represent the most sensitive WTTSs survey in the mid- to far-infrared to date and reveal the frequency of outer disks (r = 3-50 AU) around WTTSs. The 70 \u03bcm photometry for half the c2d WTTSs sample (the on-cloud objects), which were not included in the earlier papers in this series, those of Padgett et al. and Cieza et al., are presented here for the first time. We find a disk frequency of 19% for on-cloud WTTSs, but just 5% for off-cloud WTTSs, similar to the value reported in the earlier works. WTTSs exhibit spectral energy distributions that are quite diverse, spanning the range from optically thick to optically thin disks. Most disks become more tenuous than L_disk/L_* = 2 \u00d7 10^(\u20133) in 2 Myr and more tenuous than L_disk/L_* = 5 \u00d7 10^(\u20134) in 4 Myr.", "doi": "10.1088/0004-637X/724/2/835", "issn": "0004-637X", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal", "publication_date": "2010-12-01", "series_number": "2", "volume": "724", "issue": "2", "pages": "835-854" }, { "id": "authors:nsys3-23m58", "collection": "authors", "collection_id": "nsys3-23m58", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100817-140251955", "type": "article", "title": "An Observed Lack of Substructure in Starless Cores", "author": [ { "family_name": "Schnee", "given_name": "Scott", "clpid": "Schnee-S-L" }, { "family_name": "Enoch", "given_name": "Melissa", "clpid": "Enoch-M-L" }, { "family_name": "Johnstone", "given_name": "Doug", "orcid": "0000-0002-6773-459X", "clpid": "Johnstone-D" }, { "family_name": "Culverhouse", "given_name": "Thomas", "clpid": "Culverhouse-T-L" }, { "family_name": "Leitch", "given_name": "Erik", "clpid": "Leitch-E-M" }, { "family_name": "Marrone", "given_name": "Daniel P.", "orcid": "0000-0002-2367-1080", "clpid": "Marrone-D-P" }, { "family_name": "Sargent", "given_name": "Anneila", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" } ], "abstract": "In this paper, we present the results of a high resolution (5'') Combined Array for Research in Millimeter-wave Astronomy and Sunyaev-Zeldovich Array survey of the 3 mm continuum emission from 11 of the brightest (at 1.1 mm) starless cores in the Perseus molecular cloud. We detect 2 of the 11 cores, both of which are composed of single structures, and the median 3\u03c3 upper limit for the non-detections is 0.2 M_\u2299 in a ~5'' beam. These results are consistent with, and as stringent as, the low detection rate of compact 3 mm continuum emission in dense cores in Perseus reported by Olmi et al. From the non-detection of multiple components in any of the 11 cores, we conclude that starless core mass functions derived from bolometer maps at resolutions range 10''-30'' (e.g., with MAMBO, SCUBA, or Bolocam) are unlikely to be significantly biased by the blending of lower mass cores with small separations. These observations provide additional evidence that the majority of starless cores in Perseus have inner density profiles shallower than r^( \u20132).", "doi": "10.1088/0004-637X/718/1/306", "issn": "0004-637X", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal", "publication_date": "2010-07-20", "series_number": "1", "volume": "718", "issue": "1", "pages": "306-313" }, { "id": "authors:snft9-1b450", "collection": "authors", "collection_id": "snft9-1b450", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100526-110237571", "type": "article", "title": "Investigating Planet Formation in Circumstellar Disks: CARMA Observations of Ry Tau and Dg Tau", "author": [ { "family_name": "Isella", "given_name": "Andrea", "orcid": "0000-0001-8061-2207", "clpid": "Isella-A" }, { "family_name": "Carpenter", "given_name": "John M.", "orcid": "0000-0003-2251-0602", "clpid": "Carpenter-J-M" }, { "family_name": "Sargent", "given_name": "Anneila I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" } ], "abstract": "We present CARMA observations of the thermal dust emission from the circumstellar disks around the young stars RY Tau and DG Tau at wavelengths of 1.3 mm and 2.8 mm. The angular resolution of the maps is as high as 0\".15, or 20 AU at the distance of the Taurus cloud, which is a factor of 2 higher than has been achieved to date at these wavelengths. The unprecedented detail of the resulting disk images enables us to address three important questions related to the formation of planets. (1) What is the radial distribution of the circumstellar dust? (2) Does the dust emission show any indication of gaps that might signify the presence of (proto-)planets? (3) Do the dust properties depend on the orbital radius? We find that modeling the disk surface density in terms of either a classical power law or the similarity solution for viscous disk evolution reproduces the observations well. Both models constrain the surface density between 15 and 50 AU to within 30% for a given dust opacity. Outside this range, the densities inferred from the two models differ by almost an order of magnitude. The 1.3 mm image from RY Tau shows two peaks separated by 0.\"2 with a decline in the dust emission toward the stellar position, which is significant at about 2\u03c3-4\u03c3. For both RY Tau and DG Tau, the dust emission at radii larger than 15 AU displays no significant deviation from an unperturbed viscous disk model. In particular, no radial gaps in the dust distribution are detected. Under reasonable assumptions, we exclude the presence of planets more massive than 5 M_J orbiting either star at distances between about 10 and 60 AU, unless such a planet is so young that there has been insufficient time to open a gap in the disk surface density. The radial variation of the dust opacity slope, \u03b2, was investigated by comparing the 1.3 mm and 2.8 mm observations. We find mean values of \u03b2 of 0.5 and 0.7 for DG Tau and RY Tau, respectively. Variations in \u03b2 are smaller than \u0394\u03b2 = 0.7 between 20 and 70 AU. These results confirm that the circumstellar dust throughout these disks differs significantly from dust in the interstellar medium.", "doi": "10.1088/0004-637X/714/2/1746", "issn": "0004-637X", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal", "publication_date": "2010-05-10", "series_number": "2", "volume": "714", "issue": "2", "pages": "1746-1761" }, { "id": "authors:xhnz9-tb851", "collection": "authors", "collection_id": "xhnz9-tb851", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150817-124811557", "type": "article", "title": "The Dust Emissivity Spectral Index in the Starless Core TMC-1C", "author": [ { "family_name": "Schnee", "given_name": "Scott", "clpid": "Schnee-S-L" }, { "family_name": "Enoch", "given_name": "Melissa", "clpid": "Enoch-M-L" }, { "family_name": "Noriega-Crespo", "given_name": "Alberto", "orcid": "0000-0002-6296-8960", "clpid": "Noriega-Crespo-A" }, { "family_name": "Sayers", "given_name": "Jack", "orcid": "0000-0002-8213-3784", "clpid": "Sayers-Jack" }, { "family_name": "Terebey", "given_name": "Susan", "clpid": "Terebey-S" }, { "family_name": "Caselli", "given_name": "Paola", "orcid": "0000-0003-1481-7911", "clpid": "Caselli-P" }, { "family_name": "Foster", "given_name": "Jonathan", "clpid": "Foster-J-B" }, { "family_name": "Goodman", "given_name": "Alyssa", "clpid": "Goodman-A-A" }, { "family_name": "Kauffmann", "given_name": "Jens", "clpid": "Kauffmann-J" }, { "family_name": "Padgett", "given_name": "Deborah", "orcid": "0000-0001-5334-5107", "clpid": "Padgett-D-L" }, { "family_name": "Rebull", "given_name": "Luisa", "orcid": "0000-0001-6381-515X", "clpid": "Rebull-L-M" }, { "family_name": "Sargent", "given_name": "Anneila", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Shetty", "given_name": "Rahul", "clpid": "Shetty-R" } ], "abstract": "In this paper, we present a dust emission map of the starless core TMC-1C taken at 2100 \u03bcm. Along with maps at 160, 450, 850, and 1200 \u03bcm, we study the dust emissivity spectral index from the (sub)millimeter spectral energy distribution, and find that it is close to the typically assumed value of \u03b2 = 2. We also map the dust temperature and column density in TMC-1C, and find that at the position of the dust peak (A_V ~ 50) the line-of-sight-averaged temperature is ~7 K. Employing simple Monte Carlo modeling, we show that the data are consistent with a constant value for the emissivity spectral index over the whole map of TMC-1C.", "doi": "10.1088/0004-637X/708/1/127", "issn": "0004-637X", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal", "publication_date": "2010-01-01", "series_number": "1", "volume": "708", "issue": "1", "pages": "127-136" }, { "id": "authors:3bhr4-hqy53", "collection": "authors", "collection_id": "3bhr4-hqy53", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20181121-105912598", "type": "book_section", "title": "Proto-planetary disks with CARMA: sub-arsecond observations at millimeter wavelengths", "book_title": "XXVII IAU General Assembly", "author": [ { "family_name": "Andrea", "given_name": "Isella", "clpid": "Andrea-I" }, { "family_name": "Carpenter", "given_name": "John M.", "orcid": "0000-0003-2251-0602", "clpid": "Carpenter-J-M" }, { "family_name": "P\u00e9rez", "given_name": "Laura", "orcid": "0000-0002-1199-9564", "clpid": "P\u00e9rez-L-M" }, { "family_name": "Sargent", "given_name": "Anneila I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" } ], "contributor": [ { "family_name": "Corbett", "given_name": "Ian F.", "clpid": "Corbett-I-F" } ], "abstract": "Using the Combined Array for Research in Millimeter-wave Astronomy (CARMA) we observed several proto-planetary disks in the dust continuum emission at 1.3 and 2.8 mm (Isella et al. 2009a, 2009b). The observations have angular resolution between 0.15 and 0.7 arcsecond, corresponding to spatial scales spanning from about the orbit of Saturn up to about the orbital radius of Pluto. The observed disks are characterized by a variety of radial profiles for the dust density. We observe inner disk clearing as well as smooth density profiles, suggesting that disks may form, or evolve, in different ways. Despite that, we find that the characteristic disk radius is correlated with the stellar age increasing from 20 AU to 100 AU over about 5 Myr. Interpreting our results in terms of the temporal evolution of a viscous \u03b1-disk, we estimate that (i) at the beginning of the disk evolution about 60% of the circumstellar material was located inside radii of 25-40 AU, (ii) that disks formed with masses from 0.05 to 0.4 solar masses and (iii) that the viscous timescale at the disk initial radius is about 0.1-0.3 Myr. Viscous disk models tightly link the surface density \u03a3(R) with the radial profile of the disk viscosity \u03bd(R)\u221d R\u03b3. We find values of \u03b3 ranging from -0.8 to 0.8, suggesting that the viscosity dependence on the orbital radius can be very different in the observed disks. We demonstrate that the similarity solution for the surface density for \u03b3 < 0 can explain the properties of some \"transitional\" disks without requiring discontinuities in the disk surface density. In the case of LkCa 15, a smooth distribution of material from few stellar radii to about 240 AU can produce both the observed SED and the spatially resolved continuum emission at millimeter wavelengths. For two sources, RY Tau and DG Tau, we observed the dust emission with a resolution as high as 0.15 arcsecond, which corresponds to a spatial scale of 20 AU at the distance of the two stars. The achieved angular resolution is a factor 2 higher than any existing observation of circumstellar disks at the same wavelengths and enable us to investigate the disk structure with unprecedent details. In particular, we present a first attempt to derive the radial profile of the slope of the dust opacity \u03b2. We find mean values of \u03b2 of 0.5 and 0.7 for DG Tau and RY Tau respectively and we exclude that \u03b2 may vary by more than \u00b10.4 between 20-70 AU. This implies that the circumstellar dust has a maximum grain size between 10 \u03bcm and few centimeters.", "doi": "10.1017/S1743921310011270", "isbn": "9781107005334", "publisher": "Cambridge University Press", "place_of_publication": "Cambridge", "publication_date": "2009-11", "pages": "738" }, { "id": "authors:6d50f-9k544", "collection": "authors", "collection_id": "6d50f-9k544", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20090808-142505545", "type": "article", "title": "Structure and Evolution of Pre-main-sequence Circumstellar Disks", "author": [ { "family_name": "Isella", "given_name": "Andrea", "orcid": "0000-0001-8061-2207", "clpid": "Isella-A" }, { "family_name": "Carpenter", "given_name": "John M.", "orcid": "0000-0003-2251-0602", "clpid": "Carpenter-J-M" }, { "family_name": "Sargent", "given_name": "Anneila I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" } ], "abstract": "We present new subarcsecond (~0\".7) Combined Array for Research in Millimeter-wave Astronomy (CARMA) observations of the 1.3 mm continuum emission from circumstellar disks around 11 low- and intermediate-mass pre-main-sequence stars. High-resolution observations for three additional sources were obtained from the literature. In all cases the disk emission is spatially resolved. We adopt a self-consistent accretion disk model based on the similarity solution for the disk surface density and constrain the dust radial density distribution on spatial scales of about 40 AU. Disk surface densities appear to be correlated with the stellar ages where the characteristic disk radius increases from ~20 AU to ~100 AU over about 5 Myr. This disk expansion is accompanied by a decrease in the mass accretion rate, suggesting that our sample disks form an evolutionary sequence. Interpreting our results in terms of the temporal evolution of a viscous \u03b1-disk, we estimate (1) that at the beginning of the disk evolution about 60% of the circumstellar material was located inside radii of 25-40 AU, (2) that disks formed with masses from 0.05 to 0.4 M\u2299 , and (3) that the viscous timescale at the disk initial radius is about 0.1-0.3 Myr. Viscous disk models tightly link the surface density \u03a3(R) with the radial profile of the disk viscosity \u03bd(R) \u221d R^\u03b3. We find values of \u03b3 ranging from \u20130.8 to 0.8, suggesting that the viscosity dependence on the orbital radius can be very different in the observed disks. Adopting the \u03b1 parameterization for the viscosity, we argue that \u03b1 must decrease with the orbital radius and that it may vary between 0.5 and 10^(\u20134). From the inferred disk initial radii we derive specific angular momenta, j, for parent cores of (0.8 \u2013 4) \u00d7 10^(\u20134) km s^(\u20131) pc. Comparison with the values of j in dense cores suggests that about 10% of core angular momentum and 30% of the core mass are conserved in the formation of the star/disk system. We demonstrate that the similarity solution for the surface density for \u03b3 < 0 can explain the properties of some \"transitional disks\" without requiring discontinuities in the disk surface density. In the case of LkCa 15, a smooth distribution of material from few stellar radii to about 240 AU can produce both the observed spectral energy distribution and the spatially resolved continuum emission at millimeter wavelengths. Finally we show that among the observed sample, TW Hya is the only object that has a disk radius comparable with the early solar nebula.", "doi": "10.1088/0004-637X/701/1/260", "issn": "0004-637X", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal", "publication_date": "2009-08-10", "series_number": "1", "volume": "701", "issue": "1", "pages": "260-282" }, { "id": "authors:mc5p1-tvr45", "collection": "authors", "collection_id": "mc5p1-tvr45", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20090917-084832246", "type": "article", "title": "Dynamically Driven Evolution of the Interstellar Medium in M51", "author": [ { "family_name": "Koda", "given_name": "Jin", "orcid": "0000-0002-8762-7863", "clpid": "Koda-Jin" }, { "family_name": "Scoville", "given_name": "Nick", "orcid": "0000-0002-0438-3323", "clpid": "Scoville-N-Z" }, { "family_name": "Sawada", "given_name": "Tsuyoshi", "clpid": "Sawada-Tsuyoshi" }, { "family_name": "La Vigne", "given_name": "Misty A.", "clpid": "La-Vigne-M-A" }, { "family_name": "Voguel", "given_name": "Stuart N.", "clpid": "Voguel-S-N" }, { "family_name": "Potts", "given_name": "Ashley E.", "clpid": "Potts-A-E" }, { "family_name": "Carpenter", "given_name": "John M.", "orcid": "0000-0003-2251-0602", "clpid": "Carpenter-J-M" }, { "family_name": "Corder", "given_name": "Stuartt A.", "clpid": "Corder-S-A" }, { "family_name": "Wright", "given_name": "Melvyn C. H.", "clpid": "Wright-M-C-H" }, { "family_name": "White", "given_name": "Stephen M.", "clpid": "White-S-M" }, { "family_name": "Zauderer", "given_name": "B. Ashley", "orcid": "0000-0003-1152-518X", "clpid": "Zauderer-B-A" }, { "family_name": "Patience", "given_name": "Jenny", "clpid": "Patience-J" }, { "family_name": "Sargent", "given_name": "Anneila I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Bock", "given_name": "Douglas C.-J.", "clpid": "Bock-D-C-J" }, { "family_name": "Hawkins", "given_name": "David", "clpid": "Hawkins-D" }, { "family_name": "Hodges", "given_name": "Mark", "clpid": "Hodges-M" }, { "family_name": "Kemball", "given_name": "Athol", "clpid": "Kemball-A" }, { "family_name": "Lamb", "given_name": "James W.", "clpid": "Lamb-J-W" }, { "family_name": "Plambeck", "given_name": "Richard L.", "clpid": "Plambeck-R-L" }, { "family_name": "Pound", "given_name": "Marc W.", "clpid": "Pound-M-W" }, { "family_name": "Scott", "given_name": "Stephen L.", "clpid": "Scott-S-L" }, { "family_name": "Teuben", "given_name": "Peter", "clpid": "Teuben-P" }, { "family_name": "Woody", "given_name": "David P.", "clpid": "Woody-D-P" } ], "abstract": "Massive star formation occurs in giant molecular clouds (GMCs); an understanding of the evolution of GMCs is a prerequisite to develop theories of star formation and galaxy evolution. We report the highest-fidelity observations of the grand-design spiral galaxy M51 in carbon monoxide (CO) emission, revealing the evolution of GMCs vis-a-vis the large-scale galactic structure and dynamics. The most massive GMCs (giant molecular associations (GMAs)) are first assembled and then broken up as the gas flow through the spiral arms. The GMAs and their H_2 molecules are not fully dissociated into atomic gas as predicted in stellar feedback scenarios, but are fragmented into smaller GMCs upon leaving the spiral arms. The remnants of GMAs are detected as the chains of GMCs that emerge from the spiral arms into interarm regions. The kinematic shear within the spiral arms is sufficient to unbind the GMAs against self-gravity. We conclude that the evolution of GMCs is driven by large-scale galactic dynamics\u2014their coagulation into GMAs is due to spiral arm streaming motions upon entering the arms, followed by fragmentation due to shear as they leave the arms on the downstream side. In M51, the majority of the gas remains molecular from arm entry through the interarm region and into the next spiral arm passage.", "doi": "10.1088/0004-637X/700/2/L132", "issn": "2041-8205", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal Letters", "publication_date": "2009-08-01", "series_number": "2", "volume": "700", "issue": "2", "pages": "L132-L136" }, { "id": "authors:69wac-xgn49", "collection": "authors", "collection_id": "69wac-xgn49", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20090721-095304193", "type": "article", "title": "Interferometric evidence for resolved warm dust in the DQ Tau system", "author": [ { "family_name": "Boden", "given_name": "Andrew F.", "clpid": "Boden-A-F" }, { "family_name": "Akeson", "given_name": "Rachel L.", "orcid": "0000-0001-9674-1564", "clpid": "Akeson-R-L" }, { "family_name": "Sargent", "given_name": "Anneila I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Carpenter", "given_name": "John M.", "orcid": "0000-0003-2251-0602", "clpid": "Carpenter-J-M" }, { "family_name": "Ciardi", "given_name": "David R.", "orcid": "0000-0002-5741-3047", "clpid": "Ciardi-D-R" }, { "family_name": "Bary", "given_name": "Jeffrey S.", "clpid": "Bary-J-S" }, { "family_name": "Skrutskie", "given_name": "Michael F.", "clpid": "Skrutskie-M-F" } ], "abstract": "We report on near-infrared (IR) interferometric observations of the double-lined pre-main sequence binary system DQ Tau. We model these data with a visual orbit for DQ Tau supported by the spectroscopic orbit and analysis of Mathieu et al. Further, DQ Tau exhibits significant near-IR excess; modeling our data requires inclusion of near-IR light from an \"excess\" source. Remarkably, the excess source is resolved in our data, similar in scale to the binary itself (~0.2 AU at apastron), rather than the larger circumbinary disk (~0.4 AU radius). Our observations support the Mathieu et al. and Carr et al. inference of significant warm material near the DQ Tau binary.", "doi": "10.1088/0004-637X/696/2/L111", "issn": "0004-637X", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal", "publication_date": "2009-05-10", "series_number": "2", "volume": "696", "issue": "2", "pages": "L111-L114" }, { "id": "authors:kvr56-d3x23", "collection": "authors", "collection_id": "kvr56-d3x23", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20090602-120719828", "type": "article", "title": "The Spitzer c2d Legacy results: star-formation rates and efficiencies; evolution and lifetimes", "author": [ { "family_name": "Evans", "given_name": "Neal J., II", "orcid": "0000-0001-5175-1777", "clpid": "Evans-N-J-II" }, { "family_name": "Dunham", "given_name": "Michael M.", "orcid": "0000-0003-0749-9505", "clpid": "Dunham-M-M" }, { "family_name": "J\u00f8rgensen", "given_name": "Jes K.", "orcid": "0000-0001-9133-8047", "clpid": "J\u00f8rgensen-J-K" }, { "family_name": "Mer\u00edn", "given_name": "Bruno", "clpid": "Mer\u00edn-B" }, { "family_name": "van Dishoeck", "given_name": "Ewine F.", "orcid": "0000-0001-7591-1907", "clpid": "van-Dishoeck-E-F" }, { "family_name": "Alcal\u00e1", "given_name": "Juan M.", "clpid": "Alcal\u00e1-J-M" }, { "family_name": "Myers", "given_name": "Philip C.", "clpid": "Myers-P-C" }, { "family_name": "Stapelfeldt", "given_name": "Karl R.", "orcid": "0000-0002-2805-7338", "clpid": "Stapelfeldt-K-R" }, { "family_name": "Huard", "given_name": "Tracy L.", "clpid": "Huard-T-L" }, { "family_name": "Allen", "given_name": "Lori E.", "clpid": "Allen-L-E" }, { "family_name": "Harvey", "given_name": "Paul M.", "clpid": "Harvey-P-M" }, { "family_name": "van Kempen", "given_name": "Tim", "clpid": "van-Kempen-T-A" }, { "family_name": "Blake", "given_name": "Geoffrey A.", "orcid": "0000-0003-0787-1610", "clpid": "Blake-G-A" }, { "family_name": "Koemer", "given_name": "David W.", "clpid": "Koemer-D-W" }, { "family_name": "Mundy", "given_name": "Lee G.", "clpid": "Mundy-L-G" }, { "family_name": "Padgett", "given_name": "Deborah L.", "orcid": "0000-0001-5334-5107", "clpid": "Padgett-D-L" }, { "family_name": "Sargent", "given_name": "Anneila I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" } ], "abstract": "The c2d Spitzer Legacy project obtained images and photometry with both IRAC and MIPS instruments for five large, nearby molecular clouds. Three of the clouds were also mapped in dust continuum emission at 1.1 mm, and optical spectroscopy has been obtained for some clouds. This paper combines information drawn from studies of individual clouds into a combined and updated statistical analysis of star-formation rates and efficiencies, numbers and lifetimes for spectral energy distribution (SED) classes, and clustering properties. Current star-formation efficiencies range from 3% to 6%; if star formation continues at current rates for 10 Myr, efficiencies could reach 15-30%. Star-formation rates and rates per unit area vary from cloud to cloud; taken together, the five clouds are producing about 260 M of stars per Myr. The star-formation surface density is more than an order of magnitude larger than would be predicted from the Kennicutt relation used in extragalactic studies, reflecting the fact that those relations apply to larger scales, where more diffuse matter is included in the gas surface density. Measured against the dense gas probed by the maps of dust continuum emission, the efficiencies are much higher, with stellar masses similar to masses of dense gas, and the current stock of dense cores would be exhausted in 1.8 Myr on average. Nonetheless, star formation is still slow compared to that expected in a free-fall time, even in the dense cores. The derived lifetime for the Class I phase is 0.54 Myr, considerably longer than some estimates. Similarly, the lifetime for the Class 0 SED class, 0.16 Myr, with the notable exception of the Ophiuchus cloud, is longer than early estimates. If photometry is corrected for estimated extinction before calculating class indicators, the lifetimes drop to 0.44 Myr for Class I and to 0.10 for Class 0. These lifetimes assume a continuous flow through the Class II phase and should be considered median lifetimes or half-lives. Star formation is highly concentrated to regions of high extinction, and the youngest objects are very strongly associated with dense cores. The great majority (90%) of young stars lie within loose clusters with at least 35 members and a stellar density of 1 M pc^(\u20133). Accretion at the sound speed from an isothermal sphere over the lifetime derived for the Class I phase could build a star of about 0.25 M , given an efficiency of 0.3. Building larger mass stars by using higher mass accretion rates could be problematic, as our data confirm and aggravate the \"luminosity problem\" for protostars. At a given T bol, the values for L bol are mostly less than predicted by standard infall models and scatter over several orders of magnitude. These results strongly suggest that accretion is time variable, with prolonged periods of very low accretion. Based on a very simple model and this sample of sources, half the mass of a star would be accreted during only 7% of the Class I lifetime, as represented by the eight most luminous objects.", "doi": "10.1088/0067-0049/181/2/321", "issn": "0067-0049", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal Supplement Series", "publication_date": "2009-04", "series_number": "2", "volume": "181", "issue": "2", "pages": "321-350" }, { "id": "authors:2a5vx-6e975", "collection": "authors", "collection_id": "2a5vx-6e975", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20090529-154225883", "type": "article", "title": "Properties of the youngest protostars in Perseus, Serpens, and Ophiuchus", "author": [ { "family_name": "Enoch", "given_name": "Melissa L.", "clpid": "Enoch-M-L" }, { "family_name": "Evans", "given_name": "Neal J., II", "orcid": "0000-0001-5175-1777", "clpid": "Evans-N-J-II" }, { "family_name": "Sargent", "given_name": "Anneila I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Glenn", "given_name": "Jason", "orcid": "0000-0001-7527-2017", "clpid": "Glenn-J" } ], "abstract": "We present an unbiased census of deeply embedded protostars in Perseus, Serpens, and Ophiuchus, assembled by combining large-scale 1.1 mm Bolocam continuum and Spitzer Legacy surveys. We identify protostellar candidates based on their mid-infrared (mid-IR) properties, correlate their positions with 1.1 mm core positions from Enoch et al. in 2006 and 2007, and Young et al. in 2006, and construct well-sampled spectral energy distributions using our extensive wavelength coverage (\u03bb = 1.25-1100 \u03bcm). Source classification based on the bolometric temperature yields a total of 39 Class 0 and 89 Class I sources in the three-cloud sample. We compare to protostellar evolutionary models using the bolometric temperature-luminosity diagram, finding a population of low-luminosity Class I sources that are inconsistent with constant or monotonically decreasing mass accretion rates. This result argues strongly for episodic accretion during the Class I phase, with more than 50% of sources in a \"sub-Shu\" (dM/dt < 10^(\u20136) M_\u2609 yr^(\u20131)) accretion state. Average spectra are compared to protostellar radiative transfer models, which match the observed spectra fairly well in Stage 0, but predict too much near-IR and too little mid-IR flux in Stage I. Finally, the relative number of Class 0 and Class I sources is used to estimate the lifetime of the Class 0 phase; the three-cloud average yields a Class 0 lifetime of 1.7 \u00b1 0.3 \u00d7 10^5 yr, ruling out an extremely rapid early accretion phase. Correcting photometry for extinction results in a somewhat shorter lifetime (1.1 \u00d7 10^5 yr). In Ophiuchus, however, we find very few Class 0 sources (N_Class 0/N_Class I ~ 0.1-0.2), similar to previous studies of that cloud. The observations suggest a consistent picture of nearly constant average accretion rate through the entire embedded phase, with accretion becoming episodic by at least the Class I stage, and possibly earlier.", "doi": "10.1088/0004-637X/692/2/973", "issn": "0004-637X", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal", "publication_date": "2009-02-20", "series_number": "2", "volume": "692", "issue": "2", "pages": "973-997" }, { "id": "authors:5rddm-v3066", "collection": "authors", "collection_id": "5rddm-v3066", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20090806-110645206", "type": "article", "title": "The gas temperature of starless cores in Perseus", "author": [ { "family_name": "Schnee", "given_name": "S.", "clpid": "Schnee-S" }, { "family_name": "Rosolowsky", "given_name": "E.", "orcid": "0000-0002-5204-2259", "clpid": "Rosolowsky-E" }, { "family_name": "Foster", "given_name": "J.", "clpid": "Foster-J" }, { "family_name": "Enoch", "given_name": "M.", "clpid": "Enoch-M" }, { "family_name": "Sargent", "given_name": "A.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" } ], "abstract": "In this paper, we study the determinants of starless core temperatures in the Perseus molecular cloud. We use NH_3 (1,1) and (2,2) observations to derive core temperatures (T_(kin)) and data from the COMPLETE Survey of Star-Forming Regions and the c2d Spitzer Legacy Survey for observations of the other core and molecular cloud properties. The kinetic temperature distribution probed by NH_3 is in the fairly narrow range of ~ 9-15 K. We find that cores within the clusters IC348 and NGC1333 are significantly warmer than \"field\" starless cores, and T_(kin) is higher within regions of larger extinction-derived column density. Starless cores in the field are warmer when they are closer to Class 0/I protostars, but this effect is not seen for those cores in clusters. For field starless cores, T_(kin) is higher in regions in which the ^(13)CO line width and the 1.1 mm flux from the core are larger, and T_(kin) is lower when the the peak column density within the core and average volume density of the core are larger. There is no correlation between T_(kin) and ^(13)CO line width, 1.1 mm flux, density, or peak column density for those cores in clusters. The temperature of the cloud material along the line of sight to the core, as measured by CO or far-infrared emission from dust, is positively correlated with core temperature when considering the collection of cores in the field and in clusters, but this effect is not apparent when the two subsamples of cores are considered separately.", "doi": "10.1088/0004-637X/691/2/1754", "issn": "0004-637X", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal", "publication_date": "2009-02-01", "series_number": "2", "volume": "691", "issue": "2", "pages": "1754-1763" }, { "id": "authors:7a3s7-2ft62", "collection": "authors", "collection_id": "7a3s7-2ft62", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:CORapjl09", "type": "article", "title": "A Resolved Ring of Debris Dust around the Solar Analog HD 107146", "author": [ { "family_name": "Corder", "given_name": "Stuartt", "clpid": "Corder-S" }, { "family_name": "Carpenter", "given_name": "John M.", "orcid": "0000-0003-2251-0602", "clpid": "Carpenter-J-M" }, { "family_name": "Sargent", "given_name": "Anneila I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Zauderer", "given_name": "B. Ashley", "orcid": "0000-0003-1152-518X", "clpid": "Zauderer-B-A" }, { "family_name": "Wright", "given_name": "Melvyn C. H.", "clpid": "Wright-M-C-H" }, { "family_name": "White", "given_name": "Stephen M.", "clpid": "White-S-M" }, { "family_name": "Woody", "given_name": "David P.", "clpid": "Woody-D-P" }, { "family_name": "Teuben", "given_name": "Peter", "clpid": "Teuben-P" }, { "family_name": "Scott", "given_name": "Stephen L.", "clpid": "Scott-S-L" }, { "family_name": "Pound", "given_name": "Marc W.", "clpid": "Pound-M-W" }, { "family_name": "Plambeck", "given_name": "Richard L.", "clpid": "Plambeck-R-L" }, { "family_name": "Lamb", "given_name": "James W.", "clpid": "Lamb-J-W" }, { "family_name": "Koda", "given_name": "Jin", "orcid": "0000-0002-8762-7863", "clpid": "Koda-Jin" }, { "family_name": "Hodges", "given_name": "Mark", "clpid": "Hodges-M" }, { "family_name": "Hawkins", "given_name": "David", "clpid": "Hawkins-D" }, { "family_name": "Bock", "given_name": "Douglas C.-J.", "clpid": "Bock-D-C-J" } ], "abstract": "We present resolved images of the dust continuum emission from the debris disk around the young (80-200 Myr) solar-type star HD 107146 with CARMA at \u03bb = 1.3 mm and the CSO at \u03bb = 350 \u03bc. Both images show that the dust emission extends over an approximately 10\" diameter region. The high-resolution (3\") CARMA image further reveals that the dust is distributed in a partial ring with significant decrease in a flux inward of 97 AU. Two prominent emission peaks appear within the ring separated by ~140\u00b0 in the position angle. The morphology of the dust emission is suggestive of dust captured into a mean motion resonance, which would imply the presence of a planet at an orbital radius of ~45-75 AU.", "doi": "10.1088/0004-637X/690/1/L65", "issn": "2041-8205", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal Letters", "publication_date": "2009-01-01", "series_number": "1", "volume": "690", "issue": "1", "pages": "L65-L68" }, { "id": "authors:tyez9-xh786", "collection": "authors", "collection_id": "tyez9-xh786", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:ENOapj08", "type": "article", "title": "The mass distribution and lifetime of prestellar cores in Perseus, Serpens, and Ophiuchus", "author": [ { "family_name": "Enoch", "given_name": "Melissa L.", "clpid": "Enoch-M-L" }, { "family_name": "Evans", "given_name": "Neal J., II", "orcid": "0000-0001-5175-1777", "clpid": "Evans-N-J-II" }, { "family_name": "Sargent", "given_name": "Anneila I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Glenn", "given_name": "Jason", "orcid": "0000-0001-7527-2017", "clpid": "Glenn-J" }, { "family_name": "Rosolowsky", "given_name": "Erik", "orcid": "0000-0002-5204-2259", "clpid": "Rosolowsky-E" }, { "family_name": "Myers", "given_name": "Philip", "clpid": "Myers-P-C" } ], "abstract": "We present an unbiased census of starless cores in Perseus, Serpens, and Ophiuchus, assembled by comparing large-scale Bolocam 1.1 mm continuum emission maps with Spitzer c2d surveys. We use the c2d catalogs to separate 108 starless from 92 protostellar cores in the 1.1 mm core samples from Enoch and Young and their coworkers. A comparison of these populations reveals the initial conditions of the starless cores. Starless cores in Perseus have similar masses but larger sizes and lower densities on average than protostellar cores, with sizes that suggest density profiles substantially flatter than \u03c1\u221dr^-2. By contrast, starless cores in Serpens are compact and have lower masses than protostellar cores; future star formation will likely result in lower mass objects than the currently forming protostars. Comparison to dynamical masses estimated from the NH3 survey of Perseus cores by Rosolowsky and coworkers suggests that most of the starless cores are likely to be gravitationally bound, and thus prestellar. The combined prestellar core mass distribution includes 108 cores and has a slope of \u03b1 = -2.3 \u00b1 0.4 for M > 0.8 M\u2609. This slope is consistent with recent measurements of the stellar initial mass function, providing further evidence that stellar masses are directly linked to the core formation process. We place a lower limit on the core-to-star efficiency of 25%. There are approximately equal numbers of prestellar and protostellar cores in each cloud; thus the dense prestellar core lifetime must be similar to the lifetime of embedded protostars, or 4.5 x 10^5 yr, with a total uncertainty of a factor of 2. Such a short lifetime suggests a dynamic, rather than quasi-static, core evolution scenario, at least at the relatively high mean densities (n > 2 x 10^4 cm^-3) to which we are sensitive.", "doi": "10.1086/589963", "issn": "0004-637X", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal", "publication_date": "2008-09-10", "series_number": "2", "volume": "684", "issue": "2", "pages": "1240-1259" }, { "id": "authors:s51t1-tr391", "collection": "authors", "collection_id": "s51t1-tr391", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:SCHNapj08", "type": "article", "title": "Dust emission from the Perseus molecular cloud", "author": [ { "family_name": "Schnee", "given_name": "S.", "clpid": "Schnee-S-L" }, { "family_name": "Li", "given_name": "J.", "clpid": "Li-J" }, { "family_name": "Goodman", "given_name": "A. A.", "clpid": "Goodman-A-A" }, { "family_name": "Sargent", "given_name": "A. I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" } ], "abstract": "Using far-infrared emission maps taken by IRAS and Spitzer and a near-infrared extinction map derived from 2MASS data, we have made dust temperature and column density maps of the Perseus molecular cloud. We show that the emission from transiently heated very small grains (VSGs) and the big grain dust emissivity vary as a function of extinction and dust temperature, with higher dust emissivities for colder grains. This variable emissivity cannot be explained by temperature gradients along the line of sight or by noise in the emission maps, but it is consistent with grain growth in the higher density and lower temperature regions. By accounting for the variations in the dust emissivity and VSG emission, we are able to map the temperature and column density of a nearby molecular cloud with better accuracy than has previously been possible.", "doi": "10.1086/590375", "issn": "0004-637X", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal", "publication_date": "2008-09-10", "series_number": "2", "volume": "684", "issue": "2", "pages": "1228-1239" }, { "id": "authors:ctsm2-vpg14", "collection": "authors", "collection_id": "ctsm2-vpg14", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:BOOapj08", "type": "article", "title": "The c2d Spitzer spectroscopic survey of ices around low-mass young stellar objects. I. H\u2082O and the 5-8 \u03bcm bands", "author": [ { "family_name": "Boogert", "given_name": "A. C. A.", "clpid": "Boogert-A-C-A" }, { "family_name": "Pontoppidan", "given_name": "K. M.", "orcid": "0000-0001-7552-1562", "clpid": "Pontoppidan-K-M" }, { "family_name": "Knez", "given_name": "C.", "clpid": "Knez-C" }, { "family_name": "Lahuis", "given_name": "F.", "clpid": "Lahuis-F" }, { "family_name": "Kessler-Silacci", "given_name": "J.", "clpid": "Kessler-Silacci-J-E" }, { "family_name": "van Dishoeck", "given_name": "E. F.", "orcid": "0000-0001-7591-1907", "clpid": "van-Dishoeck-E-F" }, { "family_name": "Blake", "given_name": "G. A.", "orcid": "0000-0003-0787-1610", "clpid": "Blake-G-A" }, { "family_name": "Augereau", "given_name": "J.-C.", "clpid": "Augereau-J-C" }, { "family_name": "Bisschop", "given_name": "S. E.", "clpid": "Bisschop-S-E" }, { "family_name": "Bottinelli", "given_name": "S.", "clpid": "Bottinelli-S" }, { "family_name": "Brooke", "given_name": "T. Y.", "clpid": "Brooke-T-Y" }, { "family_name": "Brown", "given_name": "J.", "clpid": "Brown-J" }, { "family_name": "Crapsi", "given_name": "A.", "clpid": "Crapsi-A" }, { "family_name": "Evans", "given_name": "N. J., II", "orcid": "0000-0001-5175-1777", "clpid": "Evans-N-J-II" }, { "family_name": "Fraser", "given_name": "H. J.", "clpid": "Fraser-H-J" }, { "family_name": "Geers", "given_name": "V.", "clpid": "Geers-V-C" }, { "family_name": "Huard", "given_name": "T. L.", "clpid": "Huard-T-L" }, { "family_name": "J\u00f8rgensen", "given_name": "J. K.", "orcid": "0000-0001-9133-8047", "clpid": "J\u00f8rgensen-J-K" }, { "family_name": "\u00d6berg", "given_name": "K. I.", "orcid": "0000-0001-8798-1347", "clpid": "\u00d6berg-K-I" }, { "family_name": "Allen", "given_name": "L. E.", "clpid": "Allen-L-E" }, { "family_name": "Harvey", "given_name": "P. M.", "clpid": "Harvey-P-M" }, { "family_name": "Koerner", "given_name": "D. W.", "clpid": "Koerner-D-W" }, { "family_name": "Mundy", "given_name": "L. G.", "clpid": "Mundy-L-G" }, { "family_name": "Padgett", "given_name": "D. L.", "orcid": "0000-0001-5334-5107", "clpid": "Padgett-D-L" }, { "family_name": "Sargent", "given_name": "A. I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Stapelfeldt", "given_name": "K. R.", "orcid": "0000-0002-2805-7338", "clpid": "Stapelfeldt-K-R" } ], "abstract": "To study the physical and chemical evolution of ices in solar-mass systems, a spectral survey is conducted of a\nsample of 41 low-luminosity YSOs (L ~ 0.1 - 10 L\u2609) using 3 - 38 \u03bcm Spitzer and ground-based spectra. The sample\nis complemented with previously published Spitzer spectra of background stars and with ISO spectra of well-studied\nmassive YSOs (L ~ 10\u2075 L\u2609). The long-known 6.0 and 6.85 \u03bcm bands are detected toward all sources, with the Class 0-type YSOs showing the deepest bands ever observed. The 6.0 \u03bcm band is often deeper than expected from the bending mode of pure solid H\u2082O. The additional 5 - 7 \u03bcm absorption consists of five independent components, which, by comparison to laboratory studies, must be from at least eight different carriers. Much of this absorption is due to\nsimple species likely formed by grain surface chemistry, at abundances of 1%-30% for CH\u2083OH, 3%-8% for NH\u2083, 1%-5% for HCOOH, ~6% for H\u2082CO, and ~0.3% for HCOO\u207b relative to solid H\u2082O. The 6.85 \u03bcm band has one or two carriers, of which one may be less volatile than H\u2082O. Its carrier(s) formed early in the molecular cloud evolution and do not survive in the diffuse ISM. If an NH4^+-containing salt is the carrier, its abundance relative to solid H\u2082O is ~7%, demonstrating the efficiency of low-temperature acid-base chemistry or cosmic-ray-induced reactions. Possible origins are discussed for enigmatic, very broad absorption between 5 and 8 \u03bcm. Finally, the same ices are observed toward massive and low-mass YSOs, indicating that processing by internal UV radiation fields is a minor factor in their early chemical evolution.", "doi": "10.1086/533425", "issn": "0004-637X", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal", "publication_date": "2008-05-10", "series_number": "2", "volume": "678", "issue": "2", "pages": "985-1004" }, { "id": "authors:f4rv8-49k76", "collection": "authors", "collection_id": "f4rv8-49k76", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20090510-205739734", "type": "article", "title": "Interacting coronae of two T Tauri stars : first observational evidence for solar-like helmet streamers", "author": [ { "family_name": "Massi", "given_name": "M.", "clpid": "Massi-M" }, { "family_name": "Ros", "given_name": "E.", "orcid": "0000-0001-9503-4892", "clpid": "Ros-E" }, { "family_name": "Menten", "given_name": "K. M.", "orcid": "0000-0001-6459-0669", "clpid": "Menten-K-M" }, { "family_name": "Kaufman Bernard\u00f3", "given_name": "M.", "clpid": "Kaufman Bernard\u00f3-M" }, { "family_name": "Torricelli-Ciamponi", "given_name": "G.", "clpid": "Torricelli-Ciamponi-G" }, { "family_name": "Neidh\u00f6fer", "given_name": "J.", "clpid": "Neidh\u00f6fer-J" }, { "family_name": "Boden", "given_name": "A.", "clpid": "Boden-A-F" }, { "family_name": "Boboltz", "given_name": "D.", "clpid": "Boboltz-D" }, { "family_name": "Sargent", "given_name": "A.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Torres", "given_name": "G.", "orcid": "0000-0002-5286-0251", "clpid": "Torres-G" } ], "abstract": "Context. The young binary system V773 Tau A exhibits a persistent radio flaring activity that gradually increases from a level of a few mJy at apoastron to more than 100 mJy at periastron. Interbinary collisions between very large (>15 R\u2217) magnetic structures anchored on the two rotating stars of the system have been proposed to be the origin of these periodic radio flares. Magnetic structures extended over tens of stellar radii, that can also account for the observed fast decay of the radio flares, seem to correspond to the typical solar semi-open quite extended magnetic configurations called helmet streamers.\n\nAims. We aim to find direct observational evidence for the postulated, solar-like, coronal topologies.\n\nMethods. We performed seven-consecutive-day VLBI observations at 8.4 GHz using an array consisting of the VLBA and the 100-m Effelsberg telescope. V773 Tau A was phase-referenced to QSO B0400+258.\n\nResults. Two distinctive structures appear in the radio images here presented. They happen to be associated with the primary and secondary stars of the V773 Tau A system. In one image (Fig. 2B) the two features are extended up to 18 R\u2217 each and are nearly parallel revealing the presence of two interacting helmet streamers. One image (Fig. 2E) taken a few hours after a flare monitored by the 100-m Effelsberg telescope shows one elongated fading structure substantially rotated with respect to those seen in the B run. The same decay scenario is seen in Fig. 2G for the helmet streamer associated with the other star.\n\nConclusions. This is the very first direct evidence revealing that even if the flare origin is magnetic reconnection due to interbinary collision, both stars independently emit in the radio range with structures of their own. These structures are helmet streamers, observed for the first time in stars other than the Sun. The complete extent of each helmet streamer above the stellar surface is about 24 R\u2217 which implies that they can practically interact throughout the whole orbit, even rather close to apoastron where the stellar separation is 52 R\u2217. However, the radio flares become stronger when the stars approach. Around periastron the stellar separation is only 30 R\u2217, nearly covered by a single streamer: the two streamers overlap producing the observed giant flares.", "doi": "10.1051/0004-6361:20078637", "issn": "0004-6361", "publisher": "EDP Sciences", "publication": "Astronomy and Astrophysics", "publication_date": "2008-03", "series_number": "2", "volume": "480", "issue": "2", "pages": "489-494" }, { "id": "authors:trjmg-t6p61", "collection": "authors", "collection_id": "trjmg-t6p61", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:PADapj08", "type": "article", "title": "The Spitzer c2d Survey of Large, Nearby, Interstellar Clouds. VII. Ophiuchus Observed with MIPS", "author": [ { "family_name": "Padgett", "given_name": "Deborah L.", "orcid": "0000-0001-5334-5107", "clpid": "Padgett-D-L" }, { "family_name": "Rebull", "given_name": "Luisa M.", "orcid": "0000-0001-6381-515X", "clpid": "Rebull-L-M" }, { "family_name": "Stapelfeldt", "given_name": "Karl R.", "orcid": "0000-0002-2805-7338", "clpid": "Stapelfeldt-K-R" }, { "family_name": "Chapman", "given_name": "Nicholas", "clpid": "Chapman-N-L" }, { "family_name": "Lai", "given_name": "Shih-Ping", "clpid": "Lai-Shih-Ping" }, { "family_name": "Mundy", "given_name": "Lee G.", "clpid": "Mundy-L-G" }, { "family_name": "Evans", "given_name": "Neal J., II", "orcid": "0000-0001-5175-1777", "clpid": "Evans-N-J-II" }, { "family_name": "Brooke", "given_name": "Timothy Y.", "clpid": "Brooke-T-Y" }, { "family_name": "Cieza", "given_name": "Lucas A.", "orcid": "0000-0002-2828-1153", "clpid": "Cieza-L-A" }, { "family_name": "Spiesman", "given_name": "William-J", "clpid": "Spiesman-W-J" }, { "family_name": "Noriega-Crespo", "given_name": "Alberto", "orcid": "0000-0002-6296-8960", "clpid": "Noriega-Crespo-A" }, { "family_name": "McCabe", "given_name": "Caer-Eve", "clpid": "McCabe-C-E" }, { "family_name": "Allen", "given_name": "Lori E.", "clpid": "Allen-L-E" }, { "family_name": "Blake", "given_name": "Geoffrey A.", "orcid": "0000-0003-0787-1610", "clpid": "Blake-G-A" }, { "family_name": "Harvey", "given_name": "Paul M.", "clpid": "Harvey-P-M" }, { "family_name": "Huard", "given_name": "Tracy L.", "clpid": "Huard-T-L" }, { "family_name": "J\u00f8rgensen", "given_name": "Jes K.", "orcid": "0000-0001-9133-8047", "clpid": "J\u00f8rgensen-J-K" }, { "family_name": "Koerner", "given_name": "David W.", "clpid": "Koerner-D-W" }, { "family_name": "Myers", "given_name": "Philip C.", "clpid": "Myers-P-C" }, { "family_name": "Sargent", "given_name": "Anneila I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Teuben", "given_name": "Peter", "clpid": "Teuben-P-J" }, { "family_name": "van Dishoeck", "given_name": "Ewine F.", "orcid": "0000-0001-7591-1907", "clpid": "van-Dishoeck-E-F" }, { "family_name": "Wahhaj", "given_name": "Zahed", "orcid": "0000-0001-8269-324X", "clpid": "Wahhaj-Z" }, { "family_name": "Young", "given_name": "Kaisa E.", "clpid": "Young-K-E" }, { "literal": "Spitzer Space Telescope Legacy Science Program" } ], "abstract": "We present maps of 14.4 deg^2 of the Ophiuchus dark clouds observed by the Spitzer Space Telescope Multiband Imaging Photometer for Spitzer (MIPS). These high-quality maps depict both numerous point sources and extended dust emission within the star-forming and non\u2013star-forming portions of these clouds. Using PSF-fitting photometry, we detect 5779 sources at 24 \u03bcm and 81 sources at 70 \u03bcm at the 10 \u03c3 level of significance. Three hundred twenty-three candidate young stellar objects (YSOs) were identified according to their positions on the MIPS/2MASS K versus color-magnitude diagrams, as compared to 24 \u03bcm detections in the SWIRE extragalactic survey. We find that more than half of the YSO candidates, and almost all those with protostellar Class I spectral energy distributions, are confined to the known cluster and aggregates.", "doi": "10.1086/523883", "issn": "0004-637X", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal", "publication_date": "2008-01-10", "series_number": "2", "volume": "672", "issue": "2", "pages": "1013-1037" }, { "id": "authors:5n4at-zk443", "collection": "authors", "collection_id": "5n4at-zk443", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20091029-145539934", "type": "article", "title": "Dynamical Masses for Pre-Main-Sequence Stars: A Preliminary Physical Orbit for V773 Tau A", "author": [ { "family_name": "Boden", "given_name": "Andrew F.", "clpid": "Boden-A-F" }, { "family_name": "Torres", "given_name": "Guillermo", "orcid": "0000-0002-5286-0251", "clpid": "Torres-G" }, { "family_name": "Sargent", "given_name": "Anneila I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Akeson", "given_name": "Rachel L.", "orcid": "0000-0001-9674-1564", "clpid": "Akeson-R-L" }, { "family_name": "Carpenter", "given_name": "John M.", "orcid": "0000-0003-2251-0602", "clpid": "Carpenter-J-M" }, { "family_name": "Boboltz", "given_name": "David A.", "clpid": "Boboltz-D-A" }, { "family_name": "Massi", "given_name": "Maria", "clpid": "Massi-M" }, { "family_name": "Ghez", "given_name": "Andrea M.", "orcid": "0000-0003-3230-5055", "clpid": "Ghez-A-M" }, { "family_name": "Latham", "given_name": "David W.", "orcid": "0000-0001-9911-7388", "clpid": "Latham-D-W" }, { "family_name": "Johnston", "given_name": "Kenneth J.", "clpid": "Johnston-K-J" }, { "family_name": "Menten", "given_name": "Karl M.", "orcid": "0000-0001-6459-0669", "clpid": "Menten-K-M" }, { "family_name": "Ros", "given_name": "Eduardo", "orcid": "0000-0001-9503-4892", "clpid": "Ros-E" } ], "abstract": "We report on interferometric and radial velocity observations of the double-lined 51 day period binary (A) component of the quadruple pre-main-sequence (PMS) system V773 Tau. With these observations we have estimated preliminary visual and physical orbits of the V773 Tau A subsystem. Among other parameters, our orbit model includes an inclination of 66.0\u00b0 \u00b1 2.4\u00b0 and allows us to infer the component dynamical masses and system distance. In particular, we find component masses of 1.54 \u00b1 0.14 and 1.332 \u00b1 0.097 M_\u2299 for the Aa (primary) and Ab (secondary) components, respectively. Our modeling of the subsystem component spectral energy distributions finds temperatures and luminosities consistent with previous studies and, coupled with the component mass estimates, allows for comparison with PMS stellar models in the intermediate-mass range. We compare V773 Tau A component properties with several popular solar composition models for intermediate-mass PMS stars. All models predict masses consistent to within 2 \u03c3 of the dynamically determined values, although some models predict values that are more consistent than others.", "doi": "10.1086/521296", "issn": "0004-637X", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal", "publication_date": "2007-12-01", "series_number": "2", "volume": "670", "issue": "2", "pages": "1214-1224" }, { "id": "authors:pnjhg-96f48", "collection": "authors", "collection_id": "pnjhg-96f48", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:AKEapj07", "type": "article", "title": "The circumbinary disk of HD 98800B: Evidence for disk warping", "author": [ { "family_name": "Akeson", "given_name": "R. L.", "orcid": "0000-0001-9674-1564", "clpid": "Akeson-R-L" }, { "family_name": "Rice", "given_name": "W. K. M.", "clpid": "Rice-W-K-M" }, { "family_name": "Boden", "given_name": "A. F.", "clpid": "Boden-A-F" }, { "family_name": "Sargent", "given_name": "A. I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Carpenter", "given_name": "J. M.", "orcid": "0000-0003-2251-0602", "clpid": "Carpenter-J-M" }, { "family_name": "Bryden", "given_name": "G.", "clpid": "Bryden-G" } ], "abstract": "The quadruple young stellar system HD 98800 consists of two spectroscopic binary pairs with a circumbinary disk around the B component. Recent work by Boden and collaborators using infrared interferometry and radial velocity data resulted in a determination of the physical orbit for HD 98800B. We use the resulting inclination of the binary and the measured extinction toward the B component stars to constrain the distribution of circumbinary material. Although a standard optically and geometrically thick disk model can reproduce the spectral energy distribution, it cannot account for the observed extinction if the binary and the disk are coplanar. We next constructed a dynamical model to investigate the influence of the A component, which is not in the Ba\u2010Bb orbital plane, on the B disk. We find that these interactions have a substantial impact on the inclination of the B circumbinary disk with respect to the Ba\u2010Bb orbital plane. The resulting warp would be sufficient to place material into the line of sight and the noncoplanar disk orientation may also cause the upper layers of the disk to intersect the line of sight if the disk is geometrically thick. These simulations also support that the dynamics of the Ba\u2010Bb orbit clear the inner region to a radius of~3 AU. We then discuss whether the somewhat unusual properties of the HD 98800B disk are consistent with material remnant from the star formation process or with more recent creation by collisions from larger bodies.", "doi": "10.1086/522579", "issn": "0004-637X", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal", "publication_date": "2007-12-01", "series_number": "2", "volume": "670", "issue": "2", "pages": "1240-1246" }, { "id": "authors:xmv50-yve92", "collection": "authors", "collection_id": "xmv50-yve92", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100722-073942887", "type": "book_section", "title": "Preliminary physical orbit of the HD 98800 B system", "book_title": "The power of optical/IR interferometry : recent scientfic results and 2nd generation instrumentation", "author": [ { "family_name": "Boden", "given_name": "Andy", "clpid": "Boden-A" }, { "family_name": "Sargent", "given_name": "Anneila", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Akeson", "given_name": "Rachel", "orcid": "0000-0001-9674-1564", "clpid": "Akeson-R-L" }, { "family_name": "Carpenter", "given_name": "John", "clpid": "Carpenter-J" } ], "abstract": "As a part of a larger program to measure physical properties of PMS\nbinary systems, we have observed the PMS quadruple system HD 98800 (aka TW\nHya 4A) with the Keck Interferometer (KI), and resolved the two separate spectroscopic\nbinary components of the system. In particular we have observed the HD\n98800 North (B) binary component on multiple epochs, and integrating our data\nwith the double-lined spectroscopic orbit from Torres et al [15] has allowed us to estimate\na physical orbit for the B system. This orbit in turn yields relatively accurate\n(8%) mass estimates of the component stars, and an independent system distance\nand component luminosity estimates. Comparisons between the estimated physical\nparameters for the low-mass HD 98800 B components with mass-luminosity models\nof PMS stars, and implications for the age of HD 98800 are discussed.", "doi": "10.1007/978-3-540-74256-2_34", "isbn": "978-3-540-74253-1", "publisher": "Springer", "place_of_publication": "Berlin", "publication_date": "2007-10-12", "pages": "281-285" }, { "id": "authors:bcmm0-y7c61", "collection": "authors", "collection_id": "bcmm0-y7c61", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20091028-091148540", "type": "article", "title": "The Spitzer c2d Survey of Large, Nearby, Interstellar Clouds. IV. Lupus Observed with MIPS", "author": [ { "family_name": "Chapman", "given_name": "Nicholas L.", "clpid": "Chapman-N-L" }, { "family_name": "Lai", "given_name": "Shih-Ping", "clpid": "Lai-Shih-Ping" }, { "family_name": "Mundy", "given_name": "Lee G.", "clpid": "Mundy-L-G" }, { "family_name": "Evans", "given_name": "Neal J., II", "orcid": "0000-0001-5175-1777", "clpid": "Evans-N-J-II" }, { "family_name": "Brooke", "given_name": "Timothy Y.", "clpid": "Brooke-T-Y" }, { "family_name": "Cieza", "given_name": "Lucas A.", "orcid": "0000-0002-2828-1153", "clpid": "Cieza-L-A" }, { "family_name": "Spiesman", "given_name": "William J.", "clpid": "Spiesman-W-J" }, { "family_name": "Rebull", "given_name": "Luisa M.", "orcid": "0000-0001-6381-515X", "clpid": "Rebull-L-M" }, { "family_name": "Stapelfeldt", "given_name": "Karl R.", "orcid": "0000-0002-2805-7338", "clpid": "Stapelfeldt-K-R" }, { "family_name": "Noriega-Crespo", "given_name": "Alberto", "orcid": "0000-0002-6296-8960", "clpid": "Noriega-Crespo-A" }, { "family_name": "Lanz", "given_name": "Lauranne", "orcid": "0000-0002-3249-8224", "clpid": "Lanz-L" }, { "family_name": "Allen", "given_name": "Lori E.", "clpid": "Allen-L-E" }, { "family_name": "Blake", "given_name": "Geoffrey A.", "orcid": "0000-0003-0787-1610", "clpid": "Blake-G-A" }, { "family_name": "Bourke", "given_name": "Tyler L.", "clpid": "Bourke-T-L" }, { "family_name": "Harvey", "given_name": "Paul M.", "clpid": "Harvey-P-M" }, { "family_name": "Huard", "given_name": "Tracy L.", "clpid": "Huard-T-L" }, { "family_name": "J\u00f8rgensen", "given_name": "Jes K.", "orcid": "0000-0001-9133-8047", "clpid": "J\u00f8rgensen-J-K" }, { "family_name": "Koerner", "given_name": "David W.", "clpid": "Koerner-D-W" }, { "family_name": "Myers", "given_name": "Philip C.", "clpid": "Myers-P-C" }, { "family_name": "Padgett", "given_name": "Deborah L.", "orcid": "0000-0001-5334-5107", "clpid": "Padgett-D-L" }, { "family_name": "Sargent", "given_name": "Annelia I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Teuben", "given_name": "Peter", "clpid": "Teuben-P-J" }, { "family_name": "van Dishoeck", "given_name": "Ewine F.", "orcid": "0000-0001-7591-1907", "clpid": "van-Dishoeck-E-F" }, { "family_name": "Wahhaj", "given_name": "Zahed", "orcid": "0000-0001-8269-324X", "clpid": "Wahhaj-Z" }, { "family_name": "Young", "given_name": "Kaisa E.", "clpid": "Young-K-E" } ], "abstract": "We present maps of 7.78 deg^2 of the Lupus molecular cloud complex at 24, 70, and 160 \u03bcm. They were made with the Spitzer Space Telescope Multiband Imaging Photometer for Spitzer (MIPS) instrument as part of the Spitzer Legacy Program \"From Molecular Cores to Planet-Forming Disks\" (c2d). The maps cover three separate regions in Lupus, denoted I, III, and IV. We discuss the c2d pipeline and how our data processing differs from it. We compare source counts in the three regions with two other data sets and predicted star counts from the Wainscoat model. This comparison shows the contribution from background galaxies in Lupus I. We also create two color-magnitude diagrams using the 2MASS and MIPS data. From these results, we can identify background galaxies and distinguish them from probable young stellar objects. The sources in our catalogs are classified based on their spectral energy distribution (SED) from 2MASS and Spitzer wavelengths to create a sample of young stellar object candidates. From 2MASS data, we create extinction maps for each region and note a strong correspondence between the extinction and the 160 \u03bcm emission. The masses we derived in each Lupus cloud from our extinction maps are compared to masses estimated from ^(13)CO and C^(18) O and found to be similar to our extinction masses in some regions, but significantly different in others. Finally, based on our color-magnitude diagrams, we selected 12 of our reddest candidate young stellar objects for individual discussion. Five of the 12 appear to be newly discovered YSOs.", "doi": "10.1086/520790", "issn": "0004-637X", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal", "publication_date": "2007-09-20", "series_number": "1", "volume": "667", "issue": "1", "pages": "288-302" }, { "id": "authors:trspt-ma582", "collection": "authors", "collection_id": "trspt-ma582", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:ENOapj07", "type": "article", "title": "Comparing star formation on large scales in the c2d legacy clouds: Bolocam 1.1 mm dust continuum surveys of Serpens, Perseus, and Ophiuchus", "author": [ { "family_name": "Enoch", "given_name": "Melissa L.", "clpid": "Enoch-M-L" }, { "family_name": "Glenn", "given_name": "Jason", "orcid": "0000-0001-7527-2017", "clpid": "Glenn-J" }, { "family_name": "Evans", "given_name": "Neal J., II", "orcid": "0000-0001-5175-1777", "clpid": "Evans-N-J-II" }, { "family_name": "Sargent", "given_name": "Anneila I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Young", "given_name": "Kaisa E.", "clpid": "Young-K-E" }, { "family_name": "Huard", "given_name": "Tracy L.", "clpid": "Huard-T-L" } ], "abstract": "We have undertaken an unprecedentedly large 1.1 mm continuum survey of three nearby star-forming clouds using Bolocam at the Caltech Submillimeter Observatory. We mapped the largest areas in each cloud at millimeter or submillimeter wavelengths to date: 7.5 deg2 in Perseus (Enoch and coworkers), 10.8 deg^2 in Ophiuchus (Young and coworkers), and 1.5 deg2 in Serpens with a resolution of 31\", detecting 122, 44, and 35 cores, respectively. Here we report on results of the Serpens survey and compare the three clouds. Average measured angular core sizes and their dependence on resolution suggest that many of the observed sources are consistent with power-law density profiles. Tests of the effects of cloud distance reveal that linear resolution strongly affects measured source sizes and densities, but not the shape of the mass distribution. Core mass distribution slopes in Perseus and Ophiuchus (\u03b1 = 2.1 \u00b1 0.1 and 2.1 \u00b1 0.3) are consistent with recent measurements of the stellar IMF, whereas the Serpens distribution is flatter (\u03b1 = 1.6 \u00b1 0.2). We also compare the relative mass distribution shapes to predictions from turbulent fragmentation simulations. Dense cores constitute less than 10% of the total cloud mass in all three clouds, consistent with other measurements of low star formation efficiencies. Furthermore, most cores are found at high column densities; more than 75% of 1.1 mm cores are associated with AV ~> 8 mag in Perseus, 15 mag in Serpens, and 20-23 mag in Ophiuchus.", "doi": "10.1086/520321", "issn": "0004-637X", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal", "publication_date": "2007-09-10", "series_number": "2", "volume": "666", "issue": "2", "pages": "982-1001" }, { "id": "authors:d6te1-acd87", "collection": "authors", "collection_id": "d6te1-acd87", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100315-113431132", "type": "article", "title": "The Spitzer c2d Survey of Large, Nearby, Interstellar Clouds. VI. Perseus Observed with MIPS", "author": [ { "family_name": "Rebull", "given_name": "L. M.", "orcid": "0000-0001-6381-515X", "clpid": "Rebull-L-M" }, { "family_name": "Stapelfeldt", "given_name": "K. R.", "orcid": "0000-0002-2805-7338", "clpid": "Stapelfeldt-K-R" }, { "family_name": "Evans", "given_name": "N. J., II", "orcid": "0000-0001-5175-1777", "clpid": "Evans-N-J-II" }, { "family_name": "J\u00f8rgensen", "given_name": "J. K.", "orcid": "0000-0001-9133-8047", "clpid": "J\u00f8rgensen-J-K" }, { "family_name": "Harvey", "given_name": "P. M.", "clpid": "Harvey-P-M" }, { "family_name": "Brooke", "given_name": "T. Y.", "clpid": "Brooke-T-Y" }, { "family_name": "Bourke", "given_name": "T. L.", "clpid": "Bourke-T-L" }, { "family_name": "Padgett", "given_name": "D. L.", "orcid": "0000-0001-5334-5107", "clpid": "Padgett-D-L" }, { "family_name": "Chapman", "given_name": "N. L.", "clpid": "Chapman-N-L" }, { "family_name": "Lai", "given_name": "S.-P.", "clpid": "Lai-Shih-Ping" }, { "family_name": "Spiesman", "given_name": "W. J.", "clpid": "Spiesman-W-J" }, { "family_name": "Noriega-Crespo", "given_name": "A.", "orcid": "0000-0002-6296-8960", "clpid": "Noriega-Crespo-A" }, { "family_name": "Mer\u00edn", "given_name": "B.", "clpid": "Mer\u00edn-B" }, { "family_name": "Huard", "given_name": "T.", "clpid": "Huard-T" }, { "family_name": "Allen", "given_name": "L. E.", "clpid": "Allen-L-E" }, { "family_name": "Blake", "given_name": "G. A.", "orcid": "0000-0003-0787-1610", "clpid": "Blake-G-A" }, { "family_name": "Jarrett", "given_name": "T.", "orcid": "0000-0002-4939-734X", "clpid": "Jarrett-T-H" }, { "family_name": "Koerner", "given_name": "D. W.", "clpid": "Koerner-D-W" }, { "family_name": "Mundy", "given_name": "L. G.", "clpid": "Mundy-L-G" }, { "family_name": "Myers", "given_name": "P. C.", "clpid": "Myers-P-C" }, { "family_name": "Sargent", "given_name": "A. I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "van Dishoeck", "given_name": "E. F.", "orcid": "0000-0001-7591-1907", "clpid": "van-Dishoeck-E-F" }, { "family_name": "Wahhaj", "given_name": "Z.", "orcid": "0000-0001-8269-324X", "clpid": "Wahhaj-Z" }, { "family_name": "Young", "given_name": "K. E.", "clpid": "Young-K-E" } ], "abstract": "We present observations of 10.6 deg^2 of the Perseus molecular cloud at 24, 70, and 160 \u03bcm with Spitzer MIPS. The images show prominent, complex extended emission dominated by illuminating B stars on the east side of the cloud and by cold filaments of 160 \u03bcm emission on the west side. Of 3950 point sources identified at 24 \u03bcm, 1141 have 2MASS counterparts. A quarter of these populate regions of the K_s versus K_s - [24] diagram that are distinct from stellar photospheres and background galaxies and thus are likely to be cloud members with infrared excess. Nearly half (46%) of these 24 \u03bcm excess sources are distributed outside the IC 348 and NGC 1333 clusters. A significant number of IRAS PSC objects are not recovered by Spitzer MIPS, most often because the IRAS objects were confused by bright nebulosity. The intercluster region contains several tightly clumped (r ~ 0.1 pc) young stellar aggregates whose members exhibit a wide variety of infrared SEDs characteristic of different circumstellar environments. This could be explained by a significant age spread among the aggregate members, or if the members formed at the same time, a remarkably rapid circumstellar evolution would be required to account for the association of Class I and Class III sources at ages \u22721 Myr. We highlight important results for the HH 211 flow, where the bow shocks are detected at both 24 and 70 \u03bcm, and for the debris disk candidate BD +31 643, where the MIPS data show the linear nebulosity to be an unrelated interstellar feature. Our data, mosaics, and catalogs are available at the Spitzer Science Archive for use by interested members of the community.", "doi": "10.1086/517607", "issn": "0067-0049", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal Supplement Series", "publication_date": "2007-08", "series_number": "2", "volume": "171", "issue": "2", "pages": "447-477" }, { "id": "authors:x0jme-f8n44", "collection": "authors", "collection_id": "x0jme-f8n44", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100917-094755422", "type": "article", "title": "The Spitzer c2d Survey of Large, Nearby, Interstellar Clouds. VIII. Serpens Observed with MIPS", "author": [ { "family_name": "Harvey", "given_name": "Paul M.", "clpid": "Harvey-P-M" }, { "family_name": "Rebull", "given_name": "Luisa M.", "orcid": "0000-0001-6381-515X", "clpid": "Rebull-L-M" }, { "family_name": "Brooke", "given_name": "Tim", "clpid": "Brooke-T-Y" }, { "family_name": "Spiesman", "given_name": "William J.", "clpid": "Spiesman-W-J" }, { "family_name": "Chapman", "given_name": "Nicholas", "clpid": "Chapman-N-L" }, { "family_name": "Huard", "given_name": "Tracy L.", "clpid": "Huard-T-L" }, { "family_name": "Evans", "given_name": "Neal J., II", "orcid": "0000-0001-5175-1777", "clpid": "Evans-N-J-II" }, { "family_name": "Cieza", "given_name": "Lucas", "orcid": "0000-0002-2828-1153", "clpid": "Cieza-L-A" }, { "family_name": "Lai", "given_name": "Shih-Ping", "clpid": "Lai-Shih-Ping" }, { "family_name": "Allen", "given_name": "Lori E.", "clpid": "Allen-L-E" }, { "family_name": "Mundy", "given_name": "Lee G.", "clpid": "Mundy-L-G" }, { "family_name": "Padgett", "given_name": "Deborah L.", "orcid": "0000-0001-5334-5107", "clpid": "Padgett-D-L" }, { "family_name": "Sargent", "given_name": "Anneila I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Stapelfeldt", "given_name": "Karl R.", "orcid": "0000-0002-2805-7338", "clpid": "Stapelfeldt-K-R" }, { "family_name": "Myers", "given_name": "Philip C.", "clpid": "Myers-P-C" }, { "family_name": "van Dishoeck", "given_name": "Ewine F.", "orcid": "0000-0001-7591-1907", "clpid": "van-Dishoeck-E-F" }, { "family_name": "Blake", "given_name": "Geoffrey A.", "orcid": "0000-0003-0787-1610", "clpid": "Blake-G-A" }, { "family_name": "Koerner", "given_name": "David W.", "clpid": "Koerner-D-W" } ], "abstract": "We present maps of 1.5 deg^2 of the Serpens dark cloud at 24, 70, and 160 \u03bcm observed with the Spitzer Space Telescope MIPS camera. We describe the observations and briefly discuss the data processing carried out by the c2d team on these data. More than 2400 compact sources have been extracted at 24 \u03bcm, nearly 100 at 70 \u03bcm, and four at 160 \u03bcm. We estimate completeness limits for our 24 \u03bcm survey from Monte Carlo tests with artificial sources inserted into the Spitzer maps. We compare source counts, colors, and magnitudes in the Serpens cloud to two reference data sets: a 0.50 deg^2 set on a low-extinction region near the dark cloud, and a 5.3 deg^2 subset of the SWIRE ELAIS N1 data that was processed through our pipeline. These results show that there is an easily identifiable population of young stellar object candidates in the Serpens cloud that is not present in either of the reference data sets. We also show a comparison of visual extinction and cool dust emission illustrating a close correlation between the two and find that the most embedded YSO candidates are located in the areas of highest visual extinction.", "doi": "10.1086/518647", "issn": "0004-637X", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal", "publication_date": "2007-07-10", "series_number": "2", "volume": "663", "issue": "2", "pages": "1139-1148" }, { "id": "authors:fs6jp-s7y26", "collection": "authors", "collection_id": "fs6jp-s7y26", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20091119-105748150", "type": "article", "title": "High-Resolution Imaging of the Dust Disk around 49 Ceti", "author": [ { "family_name": "Wahhaj", "given_name": "Z.", "orcid": "0000-0001-8269-324X", "clpid": "Wahhaj-Z" }, { "family_name": "Koerner", "given_name": "D. W.", "clpid": "Koerner-D-W" }, { "family_name": "Sargent", "given_name": "A. I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" } ], "abstract": "Subarcsecond scale Keck images of the young A1 V star, 49 Ceti, resolve emission at \u03bb = 12.5 and 17.9 \u03bcm from a disk with long axis at position angle (P.A.) 125\u00b0 \u00b1 10\u00b0 and inclination \u0444 = 60\u00b0 \u00b1 15\u00b0. At 17.9 \u03bcm, the emission is brighter and more extended toward the northwest (NW) than the southeast (SE). Modeling of the mid-infrared images combined with flux densities from the literature indicate that the bulk of the mid-infrared emission comes from very small grains (a ~ 0.1 \u03bcm) confined between 30 and 60 AU from the star. This population of dust grains contributes negligibly to the significant excess observed in the spectral energy distribution. Most of the nonphotospheric energy is radiated at longer wavelengths by an outer disk of larger grains (a ~ 15 \u03bcm), inner radius ~60 AU, and outer radius ~900 AU. Global properties of the 49 Cet disk show more affinity with the \u03b2 Pic and HR 4796A disks than with other debris disks. This may be because they are all very young (t < 20 Myr), adding strength to the argument that they are transitional objects between Herbig Ae and \"Vega-like\" A stars with more tenuous circumstellar disks.", "doi": "10.1086/512716", "issn": "0004-637X", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal", "publication_date": "2007-05-20", "series_number": "1", "volume": "661", "issue": "1", "pages": "368-373" }, { "id": "authors:gf549-mqx64", "collection": "authors", "collection_id": "gf549-mqx64", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20091117-090711714", "type": "article", "title": "The Spitzer c2d Survey of Large, Nearby, Interstellar Clouds. V. Chamaeleon II Observed with IRAC", "author": [ { "family_name": "Porras", "given_name": "Alicia", "clpid": "Porras-A" }, { "family_name": "J\u00f8rgensen", "given_name": "Jes K.", "orcid": "0000-0001-9133-8047", "clpid": "J\u00f8rgensen-J-K" }, { "family_name": "Allen", "given_name": "Lori E.", "clpid": "Allen-L-E" }, { "family_name": "Evans", "given_name": "Neal J., II", "orcid": "0000-0001-5175-1777", "clpid": "Evans-N-J-II" }, { "family_name": "Bourke", "given_name": "Tyler L.", "clpid": "Bourke-T-L" }, { "family_name": "Alcal\u00e1", "given_name": "Juan M.", "clpid": "Alcal\u00e1-J-M" }, { "family_name": "Dunham", "given_name": "Michael M.", "orcid": "0000-0003-0749-9505", "clpid": "Dunham-M-M" }, { "family_name": "Blake", "given_name": "Geoffrey A.", "orcid": "0000-0003-0787-1610", "clpid": "Blake-G-A" }, { "family_name": "Chapman", "given_name": "Nicholas", "clpid": "Chapman-N-L" }, { "family_name": "Cieza", "given_name": "Lucas", "orcid": "0000-0002-2828-1153", "clpid": "Cieza-L-A" }, { "family_name": "Harvey", "given_name": "Paul M.", "clpid": "Harvey-P-M" }, { "family_name": "Huard", "given_name": "Tracy L.", "clpid": "Huard-T-L" }, { "family_name": "Koerner", "given_name": "David W.", "clpid": "Koerner-D-W" }, { "family_name": "Mundy", "given_name": "Lee G.", "clpid": "Mundy-L-G" }, { "family_name": "Myers", "given_name": "Philip C.", "clpid": "Myers-P-C" }, { "family_name": "Padgett", "given_name": "Deborah L.", "orcid": "0000-0001-5334-5107", "clpid": "Padgett-D-L" }, { "family_name": "Sargent", "given_name": "Anneila I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Stapelfeldt", "given_name": "Karl R.", "orcid": "0000-0002-2805-7338", "clpid": "Stapelfeldt-K-R" }, { "family_name": "Teuben", "given_name": "Peter", "clpid": "Teuben-P-J" }, { "family_name": "van Dishoeck", "given_name": "Ewine F.", "orcid": "0000-0001-7591-1907", "clpid": "van-Dishoeck-E-F" }, { "family_name": "Wahhaj", "given_name": "Zahed", "orcid": "0000-0001-8269-324X", "clpid": "Wahhaj-Z" }, { "family_name": "Young", "given_name": "Kaisa E.", "clpid": "Young-K-E" } ], "abstract": "We present IRAC (3.6, 4.5, 5.8, and 8.0 \u03bcm) observations of the Chamaeleon II molecular cloud. The observed area covers about 1 deg^2 defined by A_V > 2. Analysis of the data in the 2005 c2d catalogs reveals a small number of sources (40) with properties similar to those of young stellar or substellar objects (YSOs). The surface density of these YSO candidates is low, and contamination by background galaxies appears to be substantial, especially for sources classified as Class I or flat spectral energy distribution (SED). We discuss this problem in some detail and conclude that very few of the candidate YSOs in early evolutionary stages are actually in the Cha II cloud. Using a refined set of criteria, we define a smaller, but more reliable, set of 24 YSO candidates.", "doi": "10.1086/510422", "issn": "0004-637X", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal", "publication_date": "2007-02-10", "series_number": "1", "volume": "656", "issue": "1", "pages": "493-504" }, { "id": "authors:6rnsg-f6x23", "collection": "authors", "collection_id": "6rnsg-f6x23", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20091029-082343975", "type": "article", "title": "The Spitzer c2d Survey of Nearby Dense Cores. IV. Revealing the Embedded Cluster in B59", "author": [ { "family_name": "Brooke", "given_name": "Timothy Y.", "clpid": "Brooke-T-Y" }, { "family_name": "Huard", "given_name": "Tracy L.", "clpid": "Huard-T-L" }, { "family_name": "Bourke", "given_name": "Tyler L.", "clpid": "Bourke-T-L" }, { "family_name": "Boogert", "given_name": "A. C. Adwin", "clpid": "Boogert-A-C-A" }, { "family_name": "Allen", "given_name": "Lori E.", "clpid": "Allen-L-E" }, { "family_name": "Blake", "given_name": "Geoffrey A.", "orcid": "0000-0003-0787-1610", "clpid": "Blake-G-A" }, { "family_name": "Evans", "given_name": "Neal J., II", "orcid": "0000-0001-5175-1777", "clpid": "Evans-N-J-II" }, { "family_name": "Harvey", "given_name": "Paul M.", "clpid": "Harvey-P-M" }, { "family_name": "Koerner", "given_name": "David W.", "clpid": "Koerner-D-W" }, { "family_name": "Mundy", "given_name": "Lee G.", "clpid": "Mundy-L-G" }, { "family_name": "Myers", "given_name": "Philip C.", "clpid": "Myers-P-C" }, { "family_name": "Padgett", "given_name": "Deborah L.", "orcid": "0000-0001-5334-5107", "clpid": "Padgett-D-L" }, { "family_name": "Sargent", "given_name": "Anneila I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Stapelfeldt", "given_name": "Karl R.", "orcid": "0000-0002-2805-7338", "clpid": "Stapelfeldt-K-R" }, { "family_name": "van Dishoeck", "given_name": "Ewine F.", "orcid": "0000-0001-7591-1907", "clpid": "van-Dishoeck-E-F" }, { "family_name": "Chapman", "given_name": "Nicholas", "clpid": "Chapman-N-L" }, { "family_name": "Cieza", "given_name": "Lucas", "orcid": "0000-0002-2828-1153", "clpid": "Cieza-L-A" }, { "family_name": "Dunham", "given_name": "Michael M.", "orcid": "0000-0003-0749-9505", "clpid": "Dunham-M-M" }, { "family_name": "Lai", "given_name": "Shih-Ping", "clpid": "Lai-Shih-Ping" }, { "family_name": "Porras", "given_name": "Alicia", "clpid": "Porras-A" }, { "family_name": "Spiesman", "given_name": "William", "clpid": "Spiesman-W-J" }, { "family_name": "Teuben", "given_name": "Peter J.", "clpid": "Teuben-P-J" }, { "family_name": "Young", "given_name": "Chadwick H.", "clpid": "Young-C-H" }, { "family_name": "Wahhaj", "given_name": "Zahed", "orcid": "0000-0001-8269-324X", "clpid": "Wahhaj-Z" }, { "family_name": "Lee", "given_name": "Chang Won", "clpid": "Lee-Chang-Won" } ], "abstract": "Infrared images of the dark cloud core B59 were obtained with the Spitzer Space Telescope as part of the \"Cores to Disks\" Legacy Science project. Photometry from 3.6-70 \u03bcm indicates at least 20 candidate low-mass young stars near the core, more than doubling the previously known population. Out of this group, 13 are located within ~0.1 pc in projection of the molecular gas peak, where a new embedded source is detected. Spectral energy distributions span the range from small excesses above photospheric levels to rising in the mid-infrared. One other embedded object, probably associated with the millimeter source B59-MMS1, with a bolometric luminosity L_(bol) ~ 2 L_\u2299, has extended structure at 3.6 and 4.5 \u03bcm, possibly tracing the edges of an outflow cavity. The measured extinction through the central part of the core is A_V \u2273 45 mag. The B59 core is producing young stars with a high efficiency.", "doi": "10.1086/510115", "issn": "0004-637X", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal", "publication_date": "2007-01-20", "series_number": "1", "volume": "655", "issue": "1", "pages": "364-374" }, { "id": "authors:gvte5-e1c92", "collection": "authors", "collection_id": "gvte5-e1c92", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:ARCapj06", "type": "article", "title": "The evolution of outflow-envelope interactions in low-mass protostars", "author": [ { "family_name": "Arce", "given_name": "H\u00e9ctor G.", "orcid": "0000-0001-5653-7817", "clpid": "Arce-H-G" }, { "family_name": "Sargent", "given_name": "Anneila I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" } ], "abstract": "We present multiline and continuum observations of the circumstellar environment within 10to the 4th AU of a sample of protostars to investigate how the effects of outflows on their immediate environment change over time. 12CO (1\u20130) emission probes the high-velocity molecular outflows near the protostars and demonstrates that the outflow opening angle widens as the nascent star evolves. Maps of the 13CO (1\u20130) and HCO+ (1\u20130) outflow emission show that protostellar winds erode the circumstellar envelope through the entrainment of the outer envelope gas. The spatial and velocity distribution of the dense circumstellar envelope, as well as its mass, is traced by the C to the 18th O (1\u20130) emission and also displays evolutionary changes. We show that outflows are largely responsible for these changes and propose an empirical model for the evolution of outflow-envelope interactions. In addition, some of the outflows in our sample appear to affect the chemical composition of the surrounding environment, enhancing the HCO+ abundance. Overall, our results confirm that outflows play a major role in the star formation process through their strong physical and chemical impacts on the environments of the young protostars.", "issn": "0004-637X", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal", "publication_date": "2006-08-01", "series_number": "2", "volume": "646", "issue": "2", "pages": "1070-1085" }, { "id": "authors:883bd-pw436", "collection": "authors", "collection_id": "883bd-pw436", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:JORapj06", "type": "article", "title": "The Spitzer c2d survey of large, nearby, interstellar clouds. III. Perseus observed with IRAC", "author": [ { "family_name": "J\u00f8rgensen", "given_name": "Jes K.", "orcid": "0000-0001-9133-8047", "clpid": "J\u00f8rgensen-J-K" }, { "family_name": "Harvey", "given_name": "Paul M.", "clpid": "Harvey-P-M" }, { "family_name": "Evans", "given_name": "Neal J., II", "orcid": "0000-0001-5175-1777", "clpid": "Evans-N-J-II" }, { "family_name": "Huard", "given_name": "Tracy L.", "clpid": "Huard-T-L" }, { "family_name": "Allen", "given_name": "Lori E.", "clpid": "Allen-L-E" }, { "family_name": "Porras", "given_name": "Alicia", "clpid": "Porras-A" }, { "family_name": "Blake", "given_name": "Geoffrey A.", "orcid": "0000-0003-0787-1610", "clpid": "Blake-G-A" }, { "family_name": "Bourke", "given_name": "Tyler L.", "clpid": "Bourke-T-L" }, { "family_name": "Chapman", "given_name": "Nicholas", "clpid": "Chapman-N-L" }, { "family_name": "Cieza", "given_name": "Lucas", "orcid": "0000-0002-2828-1153", "clpid": "Cieza-L-A" }, { "family_name": "Koerner", "given_name": "David W.", "clpid": "Koerner-D-W" }, { "family_name": "Lai", "given_name": "Shih-Ping", "clpid": "Lai-Shih-Ping" }, { "family_name": "Mundy", "given_name": "Lee G.", "clpid": "Mundy-L-G" }, { "family_name": "Myers", "given_name": "Philip C.", "clpid": "Myers-P-C" }, { "family_name": "Padgett", "given_name": "Deborah L.", "orcid": "0000-0001-5334-5107", "clpid": "Padgett-D-L" }, { "family_name": "Rebull", "given_name": "Luisa", "orcid": "0000-0001-6381-515X", "clpid": "Rebull-L-M" }, { "family_name": "Sargent", "given_name": "Anneila I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Spiesman", "given_name": "William", "clpid": "Spiesman-W-J" }, { "family_name": "Stapelfeldt", "given_name": "Karl R.", "orcid": "0000-0002-2805-7338", "clpid": "Stapelfeldt-K-R" }, { "family_name": "van Dishoeck", "given_name": "Ewine F.", "orcid": "0000-0001-7591-1907", "clpid": "van-Dishoeck-E-F" }, { "family_name": "Wahhaj", "given_name": "Zahed", "orcid": "0000-0001-8269-324X", "clpid": "Wahhaj-Z" }, { "family_name": "Young", "given_name": "Kaisa E.", "clpid": "Young-K-E" } ], "abstract": "We present observations of 3.86 deg to the 2nd of the Perseus molecular cloud complex with the Spitzer Space Telescope Infrared Array Camera (IRAC). The maps show strong extended emission arising from shocked H2 in outflows and from polycyclic aromatic hydrocarbon features. More than 120,000 sources are extracted toward the cloud. Based on their IRAC colors and comparison to off-cloud and extragalactic fields, we identify 400 candidate young stellar objects. About two-thirds of these are associated with the young clusters IC 348 and NGC 1333, while the last third is distributed over the remaining cloud. The young stellar objects are classified according to the slope of their spectral energy distributions. Significant differences are found between the numbers of embedded Class I objects and more evolved Class II objects in IC 348, NGC 1333 and the remaining cloud, with the embedded Class I and \"flat-spectrum\" YSOs constituting 14%, 36% and 47% of the total number of YSOs identified in each of these regions. The high number of Class I objects in the extended cloud (61% of the Class I objects in the entire cloud) suggests that a significant fraction of the current star formation occurs outside the two main clusters. Finally, we discuss a number of outflows and identify their driving sources, including the deeply embedded Class 0 sources outside the two main clusters. The Class 0 objects are detected by Spitzer and have very red [3.6] - [4.5] colors, but they do not show similarly red [5.8] - [8.0] colors. The Class 0 objects are easily identifiable in color-color diagrams but are problematic to extract automatically due to the extended emission from shocked gas or scattered light in cavities related to the associated outflows.", "doi": "10.1086/517607", "issn": "0004-637X", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal", "publication_date": "2006-07-10", "series_number": "2", "volume": "645", "issue": "2", "pages": "1246-1263" }, { "id": "authors:7j3n0-5y220", "collection": "authors", "collection_id": "7j3n0-5y220", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20110304-110358706", "type": "book_section", "title": "A complete 1.1mm survey of Perseus with Bolocam", "book_title": "Spitzer Space Telescope: New Views of the Cosmos", "author": [ { "family_name": "Enoch", "given_name": "Melissa L.", "clpid": "Enoch-M-L" }, { "family_name": "Sargent", "given_name": "Anneila I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Golwala", "given_name": "Sunil", "orcid": "0000-0002-1098-7174", "clpid": "Golwala-S-R" }, { "family_name": "Evans", "given_name": "Neal J., II", "orcid": "0000-0001-5175-1777", "clpid": "Evans-N-J-II" }, { "family_name": "Young", "given_name": "Kaisa", "clpid": "Young-K-E" }, { "family_name": "Glenn", "given_name": "Jason", "orcid": "0000-0001-7527-2017", "clpid": "Glenn-J" }, { "literal": "c2d Spitzer Legacy Team" }, { "literal": "Bolocam Team" } ], "contributor": [ { "family_name": "Armus", "given_name": "L.", "clpid": "Armus-L" }, { "family_name": "Reach", "given_name": "W. T.", "clpid": "Reach-W-T" } ], "abstract": "We have completed a 7.5 square degree \u03bb=1.1mm map of Perseus\nusing Bolocam. Our map is the largest unbiased survey of Perseus at millimeter wavelengths to date, and covers the same area as the c2d Spitzer IRAC and MIPS maps of Perseus. We find that that the mass function shape is similar to that seen in other clouds and to the local IMF. Despite the large area surveyed, few new sources are found outside the known cluster regions.", "isbn": "978-1-583812-25-9", "publisher": "Astronomical Society of the Pacific", "place_of_publication": "San Francisco, CA", "publication_date": "2006", "pages": "137-138" }, { "id": "authors:k2fqc-3s293", "collection": "authors", "collection_id": "k2fqc-3s293", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170408-142009469", "type": "article", "title": "The structure and dynamics of the dense cores in the Perseus molecular cloud complex", "author": [ { "family_name": "Olmi", "given_name": "L.", "orcid": "0000-0002-1162-7947", "clpid": "Olmi-L" }, { "family_name": "Testi", "given_name": "L.", "orcid": "0000-0003-1859-3070", "clpid": "Testi-L" }, { "family_name": "Sargent", "given_name": "A. I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" } ], "abstract": "We have produced wide-field (\u2273 0.1 deg^2) images of the molecular gas around the dense cores observed by Ladd et al. (1994) in the Perseus cloud complex in various CO (CO(1-0), ^(13)CO(1-0), C^(18)O(1-0)) and CS (CS(2-1), C^(34)S(2-1)) isotopomers, and N_2H^+(1-0), using the 16-element focal plane array operating at a wavelength of 3 mm at the Five College Radio Astronomy Observatory. We also performed mosaic observations in the N_2H^+(1-0) line and in the adjacent 3 mm continuum with the OVRO interferometer. Only within one of the observed cores we unambiguously detected a 3 mm continuum compact source with the interferometer. The single-dish large-scale maps of the densest gas, which in Perseus is concentrated within two large filamentary structures roughly aligned along a NE-SW axis, allowed us to analyse the spatial and kinematical properties of the cores and of the surrounding ambient gas. In the PER4/PER5 and PER7 regions we find that the large-scale and core velocity gradients have the same sign and similar magnitudes. In at least three cases we then find pairs of nearby cores with differences in the CS and N_2H^+ emission and in the line profile, which may have been caused by evolutionary effects. The small fraction of cores with compact continuum sources, the chemical differentiation and the inward motions observed suggest that we are observing objects in a phase preceeding the collapse and the formation of stars.", "doi": "10.1051/0004-6361:20040530", "issn": "0004-6361", "publisher": "EDP Sciences", "publication": "Astronomy & Astrophysics", "publication_date": "2005-02", "series_number": "1", "volume": "431", "issue": "1", "pages": "253-268" }, { "id": "authors:7sr0z-7dj49", "collection": "authors", "collection_id": "7sr0z-7dj49", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120918-113449930", "type": "article", "title": "Spitzer Space Telescope Spectroscopy of Ices toward Low-Mass Embedded Protostars", "author": [ { "family_name": "Boogert", "given_name": "A. C. Adwin", "clpid": "Boogert-A-C-A" }, { "family_name": "Blake", "given_name": "Geoffrey A.", "orcid": "0000-0003-0787-1610", "clpid": "Blake-G-A" }, { "family_name": "Brooke", "given_name": "Timothy Y.", "clpid": "Brooke-T-Y" }, { "family_name": "Brown", "given_name": "Joanna", "clpid": "Brown-J-M" }, { "family_name": "Morris", "given_name": "Patrick", "clpid": "Morris-P-W" }, { "family_name": "Noriega-Crespo", "given_name": "Alberto", "orcid": "0000-0002-6296-8960", "clpid": "Noriega-Crespo-A" }, { "family_name": "Padgett", "given_name": "Deborah L.", "orcid": "0000-0001-5334-5107", "clpid": "Padgett-D-L" }, { "family_name": "Sargent", "given_name": "Anneila I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Stapelfeldt", "given_name": "Karl R.", "orcid": "0000-0002-2805-7338", "clpid": "Stapelfeldt-K-R" } ], "abstract": "Sensitive 5-38 \u03bcm Spitzer Space Telescope and ground-based 3-5 \u03bcm spectra of the embedded low-mass protostars B5 IRS1 and HH 46 IRS show deep ice absorption bands superposed on steeply rising mid-infrared continua. The ices likely originate in the circumstellar envelopes. The CO_2 bending mode at 15 \u03bcm is a particularly powerful tracer of the ice composition and processing history. Toward these protostars, this band shows little evidence for thermal processing at temperatures above 50 K. Signatures of lower temperature processing are present in the CO and OCN^- bands, however. The observed CO2 profile indicates an intimate mixture with H_(2)O, but not necessarily with CH_(3)OH, in contrast to some high-mass protostars. This is consistent with the low CH_(3)OH abundance derived from the ground-based L-band spectra. The CO_2 : H_(2)O column density ratios are high in both B5 IRS1 and HH 46 IRS (~35%). Clearly, the Spitzer spectra are essential for studying ice evolution in low-mass protostellar environments and for eventually determining the relation between interstellar and solar system ices.", "doi": "10.1086/422556", "issn": "0067-0049", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal Supplement Series", "publication_date": "2004-09", "series_number": "1", "volume": "154", "issue": "1", "pages": "359-362" }, { "id": "authors:1p71a-p6391", "collection": "authors", "collection_id": "1p71a-p6391", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120927-154838196", "type": "article", "title": "A \"Starless\" Core that Isn't: Detection of a Source in the L1014 Dense Core with the Spitzer Space Telescope", "author": [ { "family_name": "Young", "given_name": "Chadwick H.", "clpid": "Young-C-H" }, { "family_name": "Brooke", "given_name": "Timothy Y.", "clpid": "Brooke-T-Y" }, { "family_name": "Sargent", "given_name": "Anneila I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Blake", "given_name": "Geoffrey A.", "orcid": "0000-0003-0787-1610", "clpid": "Blake-G-A" }, { "family_name": "Padgett", "given_name": "Deborah L.", "orcid": "0000-0001-5334-5107", "clpid": "Padgett-D-L" } ], "abstract": "We present observations of L1014, a dense core in the Cygnus region previously thought to be starless, but data from the Spitzer Space Telescope show the presence of an embedded source. We propose a model for this source that includes a cold core, heated by the interstellar radiation field, and a low-luminosity internal source. The low luminosity of the internal source suggests a substellar object. If L1014 is representative, other \"starless\" cores may turn out to harbor central sources.", "doi": "10.1086/422818", "issn": "0067-0049", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal Supplement Series", "publication_date": "2004-09", "series_number": "1", "volume": "154", "issue": "1", "pages": "396-401" }, { "id": "authors:m2rvc-9ey11", "collection": "authors", "collection_id": "m2rvc-9ey11", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20181116-111527568", "type": "book_section", "title": "Techniques of mm/sub-mm Interferometry in Star Formation", "book_title": "Star Formation at High Angular Resolution", "author": [ { "family_name": "Sargent", "given_name": "Anneila I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" } ], "contributor": [ { "family_name": "Burton", "given_name": "Michael G.", "clpid": "Burton-M-G" }, { "family_name": "Jayawardhana", "given_name": "Ray", "clpid": "Jayawardhana-R" }, { "family_name": "Bourke", "given_name": "Tyler L.", "clpid": "Bourke-T-L" } ], "abstract": "Since the earliest stages of star formation occur deep in clouds of gas and dust, they are hidden from optical view. Nevertheless, infrared and millimeter wavelength observations over the last twenty years have enabled increasingly detailed studies of the processes involved in stellar birth. High resolution, aperture synthesis imaging of the millimeter-wave radiation from dust and molecular gas in star-forming clouds has proven particularly effective. On the other hand, there can be pitfalls to be avoided in the use of mm/sub-mm interferometry techniques. Here, we consider what has been learned from currently-operating mm interferometers and the potential of the next generation of arrays.", "doi": "10.1017/S0074180900241417", "isbn": "9781583811610", "publisher": "Astronomical Society of the Pacific", "place_of_publication": "San Francisco, CA", "publication_date": "2004", "pages": "19-28" }, { "id": "authors:trpfj-gqa16", "collection": "authors", "collection_id": "trpfj-gqa16", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20181207-125031394", "type": "book_section", "title": "Gas evolution in protoplanetary disks", "book_title": "Planetary Systems in the Universe \u2013 Observation, Formation and Evolution", "author": [ { "family_name": "Thi", "given_name": "W. F.", "clpid": "Thi-W-F" }, { "family_name": "van Dishoeck", "given_name": "E. F.", "orcid": "0000-0001-7591-1907", "clpid": "van-Dishoeck-E-F" }, { "family_name": "van Zadelhoff", "given_name": "G. J.", "clpid": "van-Zadelhoff-G-J" }, { "family_name": "Blake", "given_name": "G. A.", "orcid": "0000-0003-0787-1610", "clpid": "Blake-G-A" }, { "family_name": "Mannings", "given_name": "V.", "clpid": "Mannings-V-G" }, { "family_name": "Sargent", "given_name": "A. I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Horn", "given_name": "J.", "clpid": "Horn-J" }, { "family_name": "Becklin", "given_name": "E. E.", "clpid": "Becklin-E-E" }, { "family_name": "van den Ancker", "given_name": "M. E.", "clpid": "van-den-Ancker-M-E" }, { "family_name": "Natta", "given_name": "A.", "clpid": "Natta-A" } ], "abstract": "We present the results of a study of the evolution of the gas and dust in disks around T Tauri, Herbig Ae and Vega-like stars. We observed the two lowest rotational lines of H2 with the ISO-SWS as well as ^(12)CO 3\u20132 and ^(13)CO 3\u20132 with the JCMT, and CO 6\u20135 with the CSO. The H_2 lines trace the warm (\u223d 100 K) inner region whereas the CO lines probe the colder outer disks. Substantial amounts of H_2 have been detected toward T Tauri and Herbig Ae stars, and, surprisingly, also around three Vega-like objects (49 Cet, HD 135344 and \u03b2 Pictoris). In contrast with previous conclusions derived from CO data, a significant mass of warm gas is found to persist up to ages of several tens of Myrs, suggesting that slow formation of gas-rich giant planets is possible.", "doi": "10.1017/s0074180900218317", "isbn": "9781583811764", "publisher": "Astronomical Society of the Pacific", "place_of_publication": "San Francisco, CA", "publication_date": "2004", "pages": "378-380" }, { "id": "authors:3d9fq-ndw52", "collection": "authors", "collection_id": "3d9fq-ndw52", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120918-134711209", "type": "article", "title": "Continuum and CO/HCO^+ Emission from the Disk Around the T Tauri Star LkCa 15", "author": [ { "family_name": "Qi", "given_name": "Chunhua", "orcid": "0000-0001-8642-1786", "clpid": "Qi-Chunhua" }, { "family_name": "Kessler", "given_name": "Jacqueline E.", "clpid": "Kessler-J-E" }, { "family_name": "Koerner", "given_name": "David W.", "clpid": "Koerner-D-W" }, { "family_name": "Sargent", "given_name": "Anneila I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Blake", "given_name": "Geoffrey A.", "orcid": "0000-0003-0787-1610", "clpid": "Blake-G-A" } ], "abstract": "We present Owens Valley Radio Observatory Millimeter Array \u03bb = 3.4-1.2 mm dust continuum and spectral line observations of the accretion disk encircling the T Tauri star LkCa 15. The 1.2 mm dust continuum emission is resolved and gives a minimum diameter of 190 AU and an inclination angle of 57\u00b0 \u00b1 5\u00b0. There is a noticeable but, at present, poorly constrained decrease in the continuum spectral slope with frequency that may result from the coupled processes of grain growth and dust settling. Imaging of the fairly intense emission from the lowest rotational transitions of CO, ^(13)CO, and HCO^+ reveals a rotating disk substantially larger than that observed in the dust continuum. Emission extends to ~750 AU and the characteristic radius of the disk is determined to be ~425 AU (HWHM), based on model fits to the CO velocity field. The measured line ratios demonstrate that the emission from these species is optically thick, while that from C^(18)O and H^(13)CO^+ is optically thin, or nearly so. The disk mass derived from the CO isotopologues with typical dense cloud abundances is still nearly 2 orders of magnitude less than that inferred from the dust emission, the most probable explanation being extensive molecular depletion in the cold, dense disk midplane. Thus, while CO, HCO^+, and their isotopologues are excellent tracers of the disk velocity field, they are not reliable tracers of the disk mass. N_2H^+ 1 \u2192 0 emission has also been detected which, along with HCO^+, sets a lower limit to the fractional ionization of 10^(-8) in the near-surface regions of protoplanetary disks. This first detection of N_2H^+ in circumstellar disks has also made possible a determination of the N_2/CO ratio (~2) that is at least an order of magnitude larger than those in the envelopes of young stellar objects and dense clouds. The large N_2/CO ratio indicates that our observations probe disk layers in which CO is depleted but some N_2 remains in the gas phase. Such differential depletion can lead to large variations in the fractional ionization with height in the outer reaches of circumstellar disks and may help to explain the relative nitrogen deficiency observed in comets.", "doi": "10.1086/378494", "issn": "0004-637X", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal", "publication_date": "2003-11-10", "series_number": "2", "volume": "597", "issue": "2", "pages": "986-997" }, { "id": "authors:zer6c-16748", "collection": "authors", "collection_id": "zer6c-16748", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120919-095403894", "type": "article", "title": "From Molecular Cores to Planet-forming Disks: An SIRTF Legacy Program", "author": [ { "family_name": "Evans", "given_name": "Neal J., II", "orcid": "0000-0001-5175-1777", "clpid": "Evans-N-J-II" }, { "family_name": "Allen", "given_name": "Lori E.", "clpid": "Allen-L-E" }, { "family_name": "Blake", "given_name": "Geoffrey A.", "orcid": "0000-0003-0787-1610", "clpid": "Blake-G-A" }, { "family_name": "Boogert", "given_name": "A. C. A.", "clpid": "Boogert-A-C-A" }, { "family_name": "Bourke", "given_name": "Tyler", "clpid": "Bourke-T-L" }, { "family_name": "Harvey", "given_name": "Paul M.", "clpid": "Harvey-P-M" }, { "family_name": "Kessler", "given_name": "J. E.", "clpid": "Kessler-J-E" }, { "family_name": "Koerner", "given_name": "David W.", "clpid": "Koerner-D-W" }, { "family_name": "Lee", "given_name": "Chang Won", "clpid": "Lee-Chang-Won" }, { "family_name": "Mundy", "given_name": "Lee G.", "clpid": "Mundy-L-G" }, { "family_name": "Myers", "given_name": "Philip C.", "clpid": "Myers-P-C" }, { "family_name": "Padgett", "given_name": "Deborah L.", "orcid": "0000-0001-5334-5107", "clpid": "Padgett-D-L" }, { "family_name": "Pontoppidan", "given_name": "K.", "orcid": "0000-0001-7552-1562", "clpid": "Pontoppidan-K-M" }, { "family_name": "Sargent", "given_name": "Anneila I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Stapelfeldt", "given_name": "Karl R.", "orcid": "0000-0002-2805-7338", "clpid": "Stapelfeldt-K-R" }, { "family_name": "van Dishoeck", "given_name": "Ewine F.", "orcid": "0000-0001-7591-1907", "clpid": "van-Dishoeck-E-F" }, { "family_name": "Young", "given_name": "Chadwick H.", "clpid": "Young-C-H" }, { "family_name": "Young", "given_name": "Kaisa E.", "clpid": "Young-K-E" } ], "abstract": "Crucial steps in the formation of stars and planets can be studied only at mid\u2010 to far\u2010infrared wavelengths, where the Space Infrared Telescope (SIRTF) provides an unprecedented improvement in sensitivity. We will use all three SIRTF instruments (Infrared Array Camera [IRAC], Multiband Imaging Photometer for SIRTF [MIPS], and Infrared Spectrograph [IRS]) to observe sources that span the evolutionary sequence from molecular cores to protoplanetary disks, encompassing a wide range of cloud masses, stellar masses, and star\u2010forming environments. In addition to targeting about 150 known compact cores, we will survey with IRAC and MIPS (3.6\u201370 \u03bcm) the entire areas of five of the nearest large molecular clouds for new candidate protostars and substellar objects as faint as 0.001 solar luminosities. We will also observe with IRAC and MIPS about 190 systems likely to be in the early stages of planetary system formation (ages up to about 10 Myr), probing the evolution of the circumstellar dust, the raw material for planetary cores. Candidate planet\u2010forming disks as small as 0.1 lunar masses will be detectable. Spectroscopy with IRS of new objects found in the surveys and of a select group of known objects will add vital information on the changing chemical and physical conditions in the disks and envelopes. The resulting data products will include catalogs of thousands of previously unknown sources, multiwavelength maps of about 20 deg^2 of molecular clouds, photometry of about 190 known young stars, spectra of at least 170 sources, ancillary data from ground\u2010based telescopes, and new tools for analysis and modeling. These products will constitute the foundations for many follow\u2010up studies with ground\u2010based telescopes, as well as with SIRTF itself and other space missions such as SIM, JWST, Herschel, and TPF/Darwin.", "doi": "10.1086/376697", "issn": "0004-6280", "publisher": "Astronomical Society of the Pacific", "publication": "Publications of the Astronomical Society of the Pacific", "publication_date": "2003-08", "series_number": "810", "volume": "115", "issue": "810", "pages": "965-980" }, { "id": "authors:sxaew-60b16", "collection": "authors", "collection_id": "sxaew-60b16", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180207-114858579", "type": "article", "title": "The kinematic relationship between disk and jet in the DG Tauri system", "author": [ { "family_name": "Testi", "given_name": "L.", "orcid": "0000-0003-1859-3070", "clpid": "Testi-L" }, { "family_name": "Bacciotti", "given_name": "F.", "clpid": "Bacciotti-F" }, { "family_name": "Sargent", "given_name": "A. I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Ray", "given_name": "T. P.", "clpid": "Ray-T-P" }, { "family_name": "Eisl\u00f6ffel", "given_name": "J.", "clpid": "Eisl\u00f6ffel-J" } ], "abstract": "We present high angular resolution millimeter wavelength continuum and ^(13)CO(2-1) observations of the circumstellar disk surrounding the T Tauri star DG Tauri. We show that the velocity pattern in the inner regions of the disk is consistent with Keplerian rotation about a central 0.67 M_\u2299 star. The disk rotation is also consistent with the toroidal velocity pattern in the initial channel of the optical jet, as inferred from HST spectra of the first de-projected 100 AU from the source. Our observations support the tight relationship between disk and jet kinematics postulated by the popular magneto-centrifugal models for jet formation and collimation.", "doi": "10.1051/0004-6361:20021380", "issn": "0004-6361", "publisher": "EDP Sciences", "publication": "Astronomy & Astrophysics", "publication_date": "2002-10-21", "series_number": "3", "volume": "394", "issue": "3", "pages": "L31-L34" }, { "id": "authors:8k98a-gfy47", "collection": "authors", "collection_id": "8k98a-gfy47", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190115-093812254", "type": "book_section", "title": "Multi-mission operations with the Interferometry Science Center", "book_title": "Observatory Operations to Optimize Scientific Return III", "author": [ { "family_name": "Boden", "given_name": "A. F.", "clpid": "Boden-A-F" }, { "family_name": "Akeson", "given_name": "R. L.", "orcid": "0000-0001-9674-1564", "clpid": "Akeson-R-L" }, { "family_name": "Dehghani", "given_name": "N.", "clpid": "Dehghani-N" }, { "family_name": "Jones", "given_name": "J.", "clpid": "Jones-Jeff" }, { "family_name": "Rengarajain", "given_name": "K.", "clpid": "Rengarajain-K" }, { "family_name": "Sargent", "given_name": "A. I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Sun", "given_name": "Q.", "clpid": "Sun-Quentin" } ], "contributor": [ { "family_name": "Quinn", "given_name": "Peter J.", "clpid": "Quinn-P-J" } ], "abstract": "The Interferometry Science Center (ISC) at the California Institute of Technology (Caltech) is chartered with providing science operations, data analysis support, and data archiving support for the suite of interferometry projects within the NASA Origins theme. Beginning with the Science Operations System (SOS) for the Keck Interferometer (KI), the ISC will design, implement, and operate a multi-mission facility to provide operations and support functions for NASA Origins interferometers and the scientists and engineers that use them. Future Origins interferometry projects such as the Space Interferometry Mission (SIM) will further use and extend the functionality of the ISC's multi-mission base. In this talk I will introduce the functional elements in the KI SOS; describe the common SOS core elements that KI and SIM will share; and provide prospective users of these facilities an introduction to user support model that the ISC is implementing.", "doi": "10.1117/12.460753", "isbn": "9780819446237", "publisher": "Society of Photo-optical Instrumentation Engineers (SPIE)", "place_of_publication": "Bellingham, WA", "publication_date": "2002-01-02", "pages": "164-171" }, { "id": "authors:xxgf0-g4r06", "collection": "authors", "collection_id": "xxgf0-g4r06", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190506-091500837", "type": "book_section", "title": "A Close View on the Protoplanetary Disk in the Bok Globule CB 26", "book_title": "The Origins of Stars and Planets: The VLT View", "author": [ { "family_name": "Launhardt", "given_name": "R.", "clpid": "Launhardt-R" }, { "family_name": "Stecklum", "given_name": "B.", "clpid": "Stecklum-B" }, { "family_name": "Sargent", "given_name": "A. I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" } ], "contributor": [ { "family_name": "Alves", "given_name": "Jo\u00e3o F.", "clpid": "Alves-J-F" }, { "family_name": "McCaughrean", "given_name": "Mark J.", "clpid": "McCaughrean-M-J" } ], "abstract": "We present new sub-arcsecond-resolution near-infrared polarimetric imaging and millimetre interferometry data on the circumstellar disk system in the Bok globule CB26. The data imply the presence of a M \u2265 0.01 M\u2299 edge-on-seen disk of > 400 AU in diameter, being in Keplerian rotation around a young ~0.35 M\u2299 star. The mm dust emission from the inner 200 AU is highly optically thick, but the outer parts are optically thin and made of small dust grains. Planetesimal growth in the inner disk could neither be confirmed nor excluded. We argue that the CB 26 disk is a very young protoplanetary disk and show that it is comparable to the early solar system.", "doi": "10.1007/978-3-662-40277-1_41", "isbn": "978-3-662-39255-3", "publisher": "Springer", "place_of_publication": "Berlin", "publication_date": "2002", "pages": "319-324" }, { "id": "authors:hmkb4-a4k48", "collection": "authors", "collection_id": "hmkb4-a4k48", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190502-162032876", "type": "article", "title": "A Young Protoplanetary Disk in the Bok Globule CB 26?", "author": [ { "family_name": "Launhardt", "given_name": "R.", "clpid": "Launhardt-R" }, { "family_name": "Sargent", "given_name": "A. I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" } ], "abstract": "We present subarcsecond resolution millimeter-wave images of a circumstellar disk in the Bok globule CB 26. The presence of an edge-on disk is confirmed by the dust continuum morphology and the velocity field of ^(13)CO emission, which displays a Keplerian rotation pattern about an axis perpendicular to the long axis of the dust emission. We deduce a mass of ~0.3 M_\u2609 for the obscured central star. The disk is optically thick at millimeter wavelengths inside 120 AU, has a symmetric 20\u00b0 warp beyond 120 AU, an outer radius of ~200 AU, and a mass of at least 0.1 M_\u2609. We suggest that the CB 26 system is in an intermediate stage between deeply embedded protostellar accretion disks and the more evolved, perhaps protoplanetary, disks around T Tauri stars.", "doi": "10.1086/338193", "issn": "2041-8205", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal Letters", "publication_date": "2001-12-01", "series_number": "2", "volume": "562", "issue": "2", "pages": "L173-L175" }, { "id": "authors:vd217-x4909", "collection": "authors", "collection_id": "vd217-x4909", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120918-103918089", "type": "article", "title": "H_2 and CO Emission from Disks around T Tauri and Herbig Ae Pre-Main-Sequence Stars and from Debris Disks around Young Stars: Warm and Cold Circumstellar Gas", "author": [ { "family_name": "Thi", "given_name": "W. F.", "clpid": "Thi-W-F" }, { "family_name": "van Dishoeck", "given_name": "E. F.", "orcid": "0000-0001-7591-1907", "clpid": "van-Dishoeck-E-F" }, { "family_name": "Blake", "given_name": "G. A.", "orcid": "0000-0003-0787-1610", "clpid": "Blake-G-A" }, { "family_name": "van Zadelhoff", "given_name": "G. J.", "clpid": "van-Zadelhoff-G-J" }, { "family_name": "Horn", "given_name": "J.", "clpid": "Horn-J" }, { "family_name": "Becklin", "given_name": "E. E.", "clpid": "Becklin-E-E" }, { "family_name": "Mannings", "given_name": "V.", "clpid": "Mannings-V" }, { "family_name": "Sargent", "given_name": "A. I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "van den Ancker", "given_name": "M. E.", "clpid": "van-den-Ancker-M-E" }, { "family_name": "Natta", "given_name": "A.", "clpid": "Natta-A" }, { "family_name": "Kessler", "given_name": "J.", "clpid": "Kessler-J" } ], "abstract": "We present ISO Short-Wavelength Spectrometer observations of H_2 pure-rotational line emission from the disks around low- and intermediate-mass pre-main-sequence stars as well as from young stars thought to be surrounded by debris disks. The pre-main-sequence sources have been selected to be isolated from molecular clouds and to have circumstellar disks revealed by millimeter interferometry. We detect \"warm\" (T \u2248100-200 K) H_2 gas around many sources, including tentatively the debris-disk objects. The mass of this warm gas ranges from ~ 10^(-4) M_\u2609 up to 8 x 10^(-3) and can constitute a nonnegligible fraction of the total disk mass. Complementary single-dish ^(12)CO 3-2/^(13)CO 3-2, and ^(12)CO 6-5 observations have been obtained as well. These transitions probe cooler gas at T \u2248 20-80 K. Most objects show a double-peaked CO emission profile characteristic of a disk in Keplerian rotation, consistent with interferometer data on the lower J lines. The ratios of the ^(12)CO 3-2/^(13)CO 3-2 integrated fluxes indicate that ^(12)CO 3-2 is optically thick but that ^(13)CO 3-2 is optically thin or at most moderately thick. The ^(13)CO 3-2 lines have been used to estimate the cold gas mass. If a H_2/CO conversion factor of 1 x 10^(-4) is adopted, the derived cold gas masses are factors of 10-200 lower than those deduced from 1.3 millimeter dust emission assuming a gas/dust ratio of 100, in accordance with previous studies. These findings confirm that CO is not a good tracer of the total gas content in disks since it can be photodissociated in the outer layers and frozen onto grains in the cold dense part of disks, but that it is a robust tracer of the disk velocity field. In contrast, H_2 can shield itself from photodissociation even in low-mass \"optically thin\" debris disks and can therefore survive longer. The warm gas is typically 1%-10% of the total mass deduced from millimeter continuum emission, but it can increase up to 100% or more for the debris-disk objects. Thus, residual molecular gas may persist into the debris-disk phase. No significant evolution in the H_2 CO, or dust masses is found for stars with ages in the range of 10^6-10^7 yr, although a decrease is found for the older debris-disk star \u03b2 Pictoris. The large amount of warm gas derived from H_2 raises the question of the heating mechanism(s). Radiation from the central star as well as the general interstellar radiation field heat an extended surface layer of the disk, but existing models fail to explain the amount of warm gas quantitatively. The existence of a gap in the disk can increase the area of material influenced by radiation. Prospects for future observations with ground- and space-borne observations are discussed.", "doi": "10.1086/323361", "issn": "0004-637X", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal", "publication_date": "2001-11-10", "series_number": "2", "volume": "561", "issue": "2", "pages": "1074-1094" }, { "id": "authors:72phz-kdc82", "collection": "authors", "collection_id": "72phz-kdc82", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190507-134433707", "type": "article", "title": "Millimeter-Wave Aperture Synthesis Imaging of Vega: Evidence for a Ring Arc at 95 AU", "author": [ { "family_name": "Koerner", "given_name": "D. W.", "clpid": "Koerner-D-W" }, { "family_name": "Sargent", "given_name": "A. I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Ostroff", "given_name": "N. A.", "clpid": "Ostroff-N-A" } ], "abstract": "We present the first millimeter-wave aperture synthesis map of dust around a main-sequence star. A 3'' resolution image of 1.3 mm continuum emission from Vega reveals a clump of emission 12'' from the star at a position angle (P.A.) of 45\u00b0, consistent with the location of maximum 850 \u03bcm emission in a lower resolution James Clerk Maxwell Telescope/Submillimeter Common-User Bolometric Array (SCUBA) map. The flux density is 4.0 \u00b1 0.9 mJy. Adjacent 1.3 mm peaks with flux densities of 3.4 \u00b1 1.0 and 2.8 \u00b1 0.9 mJy are located 14'' and 13'' from the star at P.A.'s of 67\u00b0 and 18\u00b0, respectively. An arclike bridge connects the two strongest peaks. There is an additional 2.4 \u00b1 0.8 mJy peak to the southwest, 11'' from the star at P.A. = 215\u00b0, and a marginal detection, 1.4 \u00b1 0.5 mJy, at the stellar position, consistent with photospheric emission. An extrapolation from the 850 \u03bcm flux, assuming F_(1.3-0.85 mm) \u221d \u03bb^(-2.8), agrees well with the total detected flux for Vega at 1.3 mm and implies a dust emissivity index \u03b2 of 0.8 We conclude that we have detected all but a very small fraction of the dust imaged by SCUBA in our aperture synthesis map and that these grains are largely confined to segments of a ring of radius 95 AU.", "doi": "10.1086/324226", "issn": "0004-637X", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal", "publication_date": "2001-10-20", "series_number": "2", "volume": "560", "issue": "2", "pages": "L181-L184" }, { "id": "authors:kb4dp-qe782", "collection": "authors", "collection_id": "kb4dp-qe782", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190507-085825820", "type": "article", "title": "Dusty Debris around Solar-Type Stars: Temporal Disk Evolution", "author": [ { "family_name": "Spangler", "given_name": "C.", "clpid": "Spangler-C" }, { "family_name": "Sargent", "given_name": "A. I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Silverstone", "given_name": "M. D.", "clpid": "Silverstone-M-D" }, { "family_name": "Becklin", "given_name": "E. E.", "clpid": "Becklin-E-E" }, { "family_name": "Zuckerman", "given_name": "B.", "clpid": "Zuckerman-B" } ], "abstract": "Using ISO-ISOPHOT, we carried out a survey of almost 150 stars to search for evidence of emission from dust orbiting young main-sequence stars, both in clusters and isolated systems. Over half of the detections are new examples of dusty stellar systems and demonstrate that such dust can be detected around numerous stars older than a few times 10^6 yr. Fluxes at 60 and either 90 or 100 \u03bcm for the new excess sources together with improved fluxes for a number of IRAS-identified sources are presented. Analysis of the excess luminosity relative to the stellar photosphere shows a systematic decline of this excess with stellar age consistent with a power-law index of -2.", "doi": "10.1086/321490", "issn": "0004-637X", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal", "publication_date": "2001-07-10", "series_number": "2", "volume": "555", "issue": "2", "pages": "932-944" }, { "id": "authors:5gf3v-mk638", "collection": "authors", "collection_id": "5gf3v-mk638", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120914-091844621", "type": "article", "title": "Substantial reservoirs of molecular hydrogen in the debris disks around young stars", "author": [ { "family_name": "Thi", "given_name": "W. F.", "clpid": "Thi-W-F" }, { "family_name": "Blake", "given_name": "G. A.", "orcid": "0000-0003-0787-1610", "clpid": "Blake-G-A" }, { "family_name": "van Dishoeck", "given_name": "E. F.", "orcid": "0000-0001-7591-1907", "clpid": "van-Dishoeck-E-F" }, { "family_name": "van Zadelhoff", "given_name": "G. J.", "clpid": "van-Zadelhoff-G-J" }, { "family_name": "Horn", "given_name": "J. M. M.", "clpid": "Horn-J-M-M" }, { "family_name": "Becklin", "given_name": "E. E.", "clpid": "Becklin-E-E" }, { "family_name": "Mannings", "given_name": "V.", "clpid": "Mannings-V" }, { "family_name": "Sargent", "given_name": "A. I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "van den Ancker", "given_name": "M. E.", "clpid": "van-den-Ancker-M-E" }, { "family_name": "Natta", "given_name": "A.", "clpid": "Natta-A" } ], "abstract": "Circumstellar accretion disks transfer matter from molecular clouds to young stars and to the sites of planet formation. The disks observed around pre-main-sequence stars have properties consistent with those expected for the pre-solar nebula from which our own Solar System formed 4.5 Gyr ago. But the 'debris' disks that encircle more than 15% of nearby main-sequence stars appear to have very small amounts of gas, based on observations of the tracer molecule carbon monoxide: these observations have yielded gas/dust ratios much less than 0.1, whereas the interstellar value is about 100 (ref. 9). Here we report observations of the lowest rotational transitions of molecular hydrogen (H2) that reveal large quantities of gas in the debris disks around the stars \u03b2 Pictoris, 49 Ceti and HD135344. The gas masses calculated from the data are several hundreds to a thousand times greater than those estimated from the CO observations, and yield gas/dust ratios of the same order as the interstellar value.", "doi": "10.1038/35051033", "issn": "0028-0836", "publisher": "Nature Publishing Group", "publication": "Nature", "publication_date": "2001-01-04", "series_number": "6816", "volume": "409", "issue": "6816", "pages": "60-63" }, { "id": "authors:23gda-pq220", "collection": "authors", "collection_id": "23gda-pq220", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190506-104023129", "type": "article", "title": "Star Formation in Clusters: Early Subclustering in the Serpens Core", "author": [ { "family_name": "Testi", "given_name": "Leonardo", "orcid": "0000-0003-1859-3070", "clpid": "Testi-L" }, { "family_name": "Sargent", "given_name": "Anneila I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Olmi", "given_name": "Luca", "orcid": "0000-0002-1162-7947", "clpid": "Olmi-L" }, { "family_name": "Onello", "given_name": "Joseph S.", "clpid": "Onello-J-S" } ], "abstract": "We present high-resolution interferometric and single-dish observations of molecular gas in the Serpens cluster-forming core. Star formation does not appear to be homogeneous throughout the core, but is localized in spatially and kinematically separated subclusters. The stellar (or protostellar) density in each of the subclusters is much higher than the mean for the entire Serpens cluster. This is the first observational evidence for the hierarchical fragmentation of protocluster cores suggested by cluster formation models.", "doi": "10.1086/312858", "issn": "0004-637X", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal", "publication_date": "2000-09-01", "series_number": "1", "volume": "540", "issue": "1", "pages": "L53-L56" }, { "id": "authors:qeyd7-wpm71", "collection": "authors", "collection_id": "qeyd7-wpm71", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190514-120758497", "type": "monograph", "title": "Search for Binary Protostars", "author": [ { "family_name": "Launhardt", "given_name": "R.", "clpid": "Launhardt-R" }, { "family_name": "Sargent", "given_name": "A. I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Zinnecker", "given_name": "H.", "clpid": "Zinnecker-H" } ], "abstract": "In an effort to shed more light on the formation process of binary stars, we have started a program to study multiplicity among nearby low- and intermediate-mass protostars using the OVRO Millimeter Array. Here, we describe the project and present the first results on the protostellar core in the Bok globule CB230 (L1177). At 10 arcsec resolution, the molecular core is resolved into two components separated by 5000 AU. The morphology and kinematics of the double core suggest that it formed from a single cloud core due to rotational fragmentation.", "doi": "10.48550/arXiv.0001486", "publication_date": "2000-01-27" }, { "id": "authors:7paf0-94n13", "collection": "authors", "collection_id": "7paf0-94n13", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120914-112337733", "type": "article", "title": "Imaging the Haro 6-10 Infrared Companion", "author": [ { "family_name": "Koresko", "given_name": "Chris D.", "clpid": "Koresko-C-D" }, { "family_name": "Blake", "given_name": "Geoffrey A.", "orcid": "0000-0003-0787-1610", "clpid": "Blake-G-A" }, { "family_name": "Brown", "given_name": "Michael E.", "orcid": "0000-0002-8255-0545", "clpid": "Brown-M-E" }, { "family_name": "Sargent", "given_name": "Anneila I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Koerner", "given_name": "David W.", "clpid": "Koerner-D-W" } ], "abstract": "We present an infrared imaging study of the low-mass pre-main-sequence binary system Haro 6-10. This system is one of a handful in which the optically visible primary has the characteristics of a normal T Tauri star, while the secondary is a so-called \"infrared companion\" (IRC), a strongly extincted object that emits most of its luminosity in the infrared. A speckle holographic technique was used to produce nearly diffraction-limited images on three nights over a 1 yr period starting in late 1997. The images show that the IRC is obscured and surrounded by a compact, irregular, and variable nebula. This structure is in striking contrast to the well-ordered edge-on disk associated with HK Tauri B, the extincted companion to another T Tauri star of similar age. A new, resolved intensity peak was found 0\".4 southwest of the IRC. We suggest that it may represent light scattered by a clump of dusty material illuminated by starlight escaping along an outflow-carved cavity in the IRC envelope. The primary star became fainter and the companion became more extended during the observing period.", "doi": "10.1086/312333", "issn": "2041-8205", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal Letters", "publication_date": "1999-11-01", "series_number": "1", "volume": "525", "issue": "1", "pages": "L49-L52" }, { "id": "authors:mhqc2-1wj81", "collection": "authors", "collection_id": "mhqc2-1wj81", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20121002-151349410", "type": "book_section", "title": "H_2 Emission From Disks Around Herbig Ae and T Tauri Stars", "book_title": "The Universe as Seen by ISO", "author": [ { "family_name": "Thi", "given_name": "W. F.", "clpid": "Thi-W-F" }, { "family_name": "van Dishoeck", "given_name": "E. F.", "orcid": "0000-0001-7591-1907", "clpid": "van-Dishoeck-E-F" }, { "family_name": "Blake", "given_name": "G. A.", "orcid": "0000-0003-0787-1610", "clpid": "Blake-G-A" }, { "family_name": "van Zadelhoff", "given_name": "G. J.", "clpid": "van-Zadelhoff-G-J" }, { "family_name": "Hogerheijde", "given_name": "M. R.", "clpid": "Hogerheijde-M-R" }, { "family_name": "Mannings", "given_name": "V.", "clpid": "Mannings-V" }, { "family_name": "Sargent", "given_name": "A. I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Becklin", "given_name": "E. E.", "clpid": "Becklin-E-E" }, { "family_name": "Horn", "given_name": "J.", "clpid": "Horn-J" }, { "family_name": "Zuckerman", "given_name": "B.", "clpid": "Zuckerman-B" }, { "family_name": "Koerner", "given_name": "D.", "clpid": "Koerner-D-W" }, { "family_name": "Mundy", "given_name": "L. G.", "clpid": "Mundy-L-G" }, { "family_name": "Waters", "given_name": "L. B. F. M.", "clpid": "Waters-L-B-F-M" }, { "family_name": "Wesselius", "given_name": "P. R.", "clpid": "Wesselius-P-R" }, { "family_name": "van den Ancker", "given_name": "M. E.", "clpid": "van-den-Ancker-M-E" }, { "family_name": "Natta", "given_name": "A.", "clpid": "Natta-A" }, { "family_name": "Waelkens", "given_name": "C.", "clpid": "Waelkens-C" }, { "family_name": "Malfait", "given_name": "K.", "clpid": "Malfait-K" } ], "contributor": [ { "family_name": "Cox", "given_name": "P.", "clpid": "Cox-Pierre" }, { "family_name": "Kessler", "given_name": "M. F.", "clpid": "Kessler-M-F" } ], "abstract": "We present the initial results of a deep ISO-SWS survey\nfor the low J pure rotational emission lines of H2\ntoward a number of Herbig Ae and T Tauri stars.\nThe objects are selected to be as isolated as possible\nfrom molecular clouds, with a spectral energy distribution\ncharacteristic of a circumstellar disk. For most\nof them the presence of a disk has been established\ndirectly by millimeter interferometry. The S (1) line is\ndetected in most sources with a peak flux of 0.3-1 Jy.\nThe S(0) line is definitely seen in 2 objects: GG Tau\nand HD 163296. The observations suggest the presence\nof \"warm\" gas at T_(kin) \u2248 100 K with a mass of a\nfew % of the total gas+ dust mass, derived assuming\na gas-to-dust ratio of 100:1. The S(1) peak flux does\nnot show a strong correlation with spectral type of\nthe central star or continuum flux at 1.3 millimeter.\nPossible origins for the warm gas seen in H_2 are discussed,\nand comparisons with model calculations are\nmade.", "isbn": "9789290927082", "publisher": "European Space Agency", "place_of_publication": "Noordwijk, Netherlands", "publication_date": "1999-03", "pages": "529-532" }, { "id": "authors:9v99g-b6b64", "collection": "authors", "collection_id": "9v99g-b6b64", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190605-160239913", "type": "book_section", "title": "Dramatic Changes in Molecular Cloud Properties Across the Arp 299 Merger", "book_title": "Galaxy Interactions at Low and High Redshift", "author": [ { "family_name": "Aalto", "given_name": "S.", "orcid": "0000-0002-5828-7660", "clpid": "Aalto-Susanne" }, { "family_name": "Radford", "given_name": "S. J. E.", "clpid": "Radford-S-J-E" }, { "family_name": "Scoville", "given_name": "N. Z.", "orcid": "0000-0002-0438-3323", "clpid": "Scoville-N-Z" }, { "family_name": "Sargent", "given_name": "A. I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" } ], "editor": [ { "family_name": "Barnes", "given_name": "J. E.", "clpid": "Barnes-J-E" }, { "family_name": "Sanders", "given_name": "D. B.", "clpid": "Sanders-D-B" } ], "abstract": "Arp 299 is an IR-luminous (L_(IR) \u2248 8 x 10^(11) L_\u2a00) merger system of two galaxies, IC 694 and NGC 3690, at a distance of 40 Mpc. Its proximity and richness in molecular gas make it suitable for studying the effects of gravitational interactions and starburst activity on molecular cloud distributions, dynamics, and physical conditions. Previous low resolution observations (10 \u2013 30\u2033) indicated that the CO/^(13)CO 1\u20130 intensity ratio is unusually high, > 20, suggesting an unusual population of molecular clouds (Aalto et al. 1991; Casoli et al. 1992).", "doi": "10.1007/978-94-011-4665-4_56", "isbn": "978-0-7923-5833-6", "publisher": "Springer", "place_of_publication": "Dordrecht", "publication_date": "1999", "pages": "231-234" }, { "id": "authors:tk1yy-yq853", "collection": "authors", "collection_id": "tk1yy-yq853", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150617-090946841", "type": "article", "title": "A rotating disk of gas and dust around a young counterpart to \u03b2 Pictoris", "author": [ { "family_name": "Mannings", "given_name": "Vincent", "clpid": "Mannings-V" }, { "family_name": "Koerner", "given_name": "David W.", "clpid": "Koerner-D-W" }, { "family_name": "Sargent", "given_name": "Anneila I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" } ], "abstract": "\u03b2 Pictoris is the best known example of a main-sequence star encircled by a tenuous disk. Optical and infrared images of \u03b2 Pic suggest that the disk is composed of dust grains which have been interpreted as the debris generated by the disruption of the asteroid-sized remnants of planet-formation processes. The star itself is relatively old, with an age in excess of 100 Myr. Here we present high-resolution millimetre-wave images of continuum and molecular-line emission from dust and gas surrounding a much younger star, MWC480: the stellar properties of MWC480 are similar to those of \u03b2 Pic, but its age is just 6 Myr. The morphology of the circumstellar material and a comparison with the predictions of kinematic modelling indicate the presence of a rotating disk, gravitationally bound to the star. Moreover, the mass of the disk is greater than the minimum required to form a planetary system like our own. We therefore suggest that the disk around the young star MWC480 could be a progenitor of debris disks of the type associated with older stars such as \u03b2 Pic, and so holds much promise for the study of both the origin of debris disks and the early stages of the formation of planetary systems.", "doi": "10.1038/41505", "issn": "0028-0836", "publisher": "Nature Publishing Group", "publication": "Nature", "publication_date": "1997-08-07", "series_number": "6642", "volume": "388", "issue": "6642", "pages": "555-557" }, { "id": "authors:xf7vg-xwg25", "collection": "authors", "collection_id": "xf7vg-xwg25", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190507-103932839", "type": "article", "title": "Variation of Molecular Line Ratios and Cloud Properties in the Arp 299 Galaxy Merger", "author": [ { "family_name": "Aalto", "given_name": "S.", "orcid": "0000-0002-5828-7660", "clpid": "Aalto-Susanne" }, { "family_name": "Radford", "given_name": "Simon J. E.", "clpid": "Radford-S-J-E" }, { "family_name": "Scoville", "given_name": "N. Z.", "orcid": "0000-0002-0438-3323", "clpid": "Scoville-N-Z" }, { "family_name": "Sargent", "given_name": "A. I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" } ], "abstract": "High-resolution observations of ^(12)CO (2.\"3),^(13)CO (3.\"9), and HCN (5.\"4) J = 1-0 in the galaxy merger Arp 299 (IC 694 and NGC 3690) show that the line ratios vary dramatically across the system. The ^(12)CO/^(13)CO ratio is unusually large, 60 \u00b1 15, at the IC 694 nucleus, where ^(12)CO emission is very strong, and much smaller, 10 \u00b1 3, in the southern extended disk of that galaxy. Elsewhere, the ^(12)CO/^(13)CO line ratio is 5-20, typical of spiral galaxies. The line ratio variation in the overlap between the two galaxies is smaller, ranging from 10 \u00b1 3 in the east to 20 \u00b1 4 in the west.\nThe ^(12)CO/HCN line ratio also varies across Arp 299, although to a lesser degree. HCN emission is bright toward each galaxy nucleus and in the extranuclear region of active star formation; it was not detected in the IC 694 disk or the eastern part of the overlap region, leading to lower limits of 25 and 20, respectively. By contrast, at the nuclei of IC 694 and NGC 3690 the ratios are 9 \u00b1 1 and 14 \u00b1 3, respectively. In the western part of the overlap region it is 11 \u00b1 3.\nThe large ^(12)CO/^(13)CO 1-0 intensity ratio at the nucleus of IC 694 can primarily be attributed to a low-to-moderate optical depth (\u03c4 \u227e 1) in the ^(12)CO 1-0 line. These data support the hypothesis that unusually high ^(12)CO/^(13)CO line ratios (>20) are associated with extremely compact molecular distributions in the nuclei of merging galaxies. Relative to ^(12)CO,^(13)CO 1-0 is brightest in quiescent regions of low ^(12)CO surface brightness and weakest in starburst regions and the galactic nuclei. A medium consisting of dense (n = 10^4-10^5 cm^(-3)) and warm (T_k > 50 K) gas will reproduce the extreme line ratios observed in the nucleus of IC 694, where the area filling factor must be at least 20%.", "doi": "10.1086/310475", "issn": "0004-637X", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal", "publication_date": "1997-02-01", "series_number": "2", "volume": "475", "issue": "2", "pages": "L107-L110" }, { "id": "authors:bq5ms-j9a50", "collection": "authors", "collection_id": "bq5ms-j9a50", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20121002-103210709", "type": "article", "title": "Search for H_2 Emission from Disks around T Tauri and Herbig AE Stars", "author": [ { "family_name": "van Dishoeck", "given_name": "E. F.", "orcid": "0000-0001-7591-1907", "clpid": "van-Dishoeck-E-F" }, { "family_name": "Thi", "given_name": "W. F.", "clpid": "Thi-W-F" }, { "family_name": "Blake", "given_name": "G. A.", "orcid": "0000-0003-0787-1610", "clpid": "Blake-G-A" }, { "family_name": "Mannings", "given_name": "V.", "clpid": "Mannings-V-G" }, { "family_name": "Sargent", "given_name": "A. I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Koerner", "given_name": "D.", "clpid": "Koerner-D-W" }, { "family_name": "Mundy", "given_name": "L. G.", "clpid": "Mundy-L-G" } ], "abstract": "Preliminary results are presented of observations of the pure rotational lines of H_2 toward T Tauri and Herbig Ae stars using the Short Wavelength Spectrometer (SWS) on the Infrared Space Observatory (ISO). The sources are selected to be isolated low- and intermediate-mass young stellar objects, for which the presence of a circumstellar disk has been established by millimeter interferometry. The lowest H_2 S(0) and S(1) lines are detected in 3 out of 5 objects. The measured intensities indicate \u223c 0.01 M_\u2299 of warm (T \u2248 150 K) gas in the ISO beam. It is argued that for at least one case (HD 163296), the emission is probably dominated by the warm gas in the circumstellar disk rather than by shocked- or photon-heated gas in the surrounding envelope. Such observations can provide important constraints on the radial and vertical temperature profiles in circumstellar disks.", "doi": "10.1023/A:1001110801449", "issn": "0004-640X", "publisher": "Springer", "publication": "Astrophysics and Space Science", "publication_date": "1997-01", "series_number": "1-2", "volume": "255", "issue": "1-2", "pages": "77-82" }, { "id": "authors:pqn9q-tyy40", "collection": "authors", "collection_id": "pqn9q-tyy40", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20201201-121035964", "type": "book_section", "title": "Protostellar and Protoplanetary Disks", "book_title": "CO: Twenty-Five Years of Millimeter-Wave Spectroscopy", "author": [ { "family_name": "Sargent", "given_name": "Anneila I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" } ], "contributor": [ { "family_name": "Latter", "given_name": "William B.", "clpid": "Latter-W-B" }, { "family_name": "Radford", "given_name": "Simon J. E.", "clpid": "Radford-S-J-E" }, { "family_name": "Jewell", "given_name": "Philip R.", "clpid": "Jewell-P-R" }, { "family_name": "Mangum", "given_name": "Jeffrey G.", "clpid": "Mangum-J-G" }, { "family_name": "Bally", "given_name": "John", "clpid": "Bally-J" } ], "abstract": "It is barely a decade since the first molecular line images of disks around embedded and pre-main sequence stars were published (Beckwith et al., 1986; Mundy et al., 1986; Sargent & Beckwith 1987). In the intervening years there has been steady progress in detecting and analyzing these disks, which are an expected by-product of the star formation process cf. Shu et al., 1987; Shu et al., 1993), and there is now a veritable flood of new and intriguing results as millimeter-wave instrumentation improves (cf. Sargent & Welch 1993).", "doi": "10.1007/978-94-011-5414-7_27", "isbn": "978-0-7923-4284-7", "publisher": "Springer", "place_of_publication": "Dordrecht", "publication_date": "1997", "pages": "151-158" }, { "id": "authors:1zbs6-6p902", "collection": "authors", "collection_id": "1zbs6-6p902", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20131030-102744787", "type": "article", "title": "ISOCAM in flight", "author": [ { "family_name": "Cesarsky", "given_name": "C. J.", "clpid": "Cesarsky-C-J" }, { "family_name": "Sargent", "given_name": "A.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" } ], "abstract": "ISOCAM, the camera on-board ISO, takes images of the sky in the wavelength range 2.5 to 18\u03bcm. It features two independent channels, containing each a 32x32 pixel detector: the short wavelength channel, 2.5 to 5.5\u03bcm, and the long wavelength channel, 4 to 18\u03bcm. Each channel features 10 or 11 discrete band pass filters and CVFs with a resolution better than 35. Each channel is fitted with a set of lenses, which reimage the focal plane of the telescope on the array, yielding a pixel field of view of 1.5, 3, 6 or 12arcsec. Throughout the development cycle, ISOCAM has been carefully calibrated, first at component level and next at instrument level. The detectors have been thoroughly tested, including exposure to gamma rays and to fast protons and nuclei. The in-flight performance of ISOCAM matches all the expectations: for instance at 15\u03bcm and 6 arcsec field of view, 200 \u03bcJy sources are detected at the 10\u03c3 level in 200 seconds.", "issn": "0004-6361", "publisher": "EDP Sciences", "publication": "Astronomy and Astrophysics", "publication_date": "1996-11", "series_number": "2", "volume": "315", "issue": "2", "pages": "L32-L37" }, { "id": "authors:5554k-se596", "collection": "authors", "collection_id": "5554k-se596", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150605-095422672", "type": "article", "title": "Circumstellar disks and the search for neighbouring planetary systems", "author": [ { "family_name": "Beckwith", "given_name": "Steven V. W.", "clpid": "Beckwith-S-V-W" }, { "family_name": "Sargent", "given_name": "Anneila I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" } ], "abstract": "The recent discoveries of planets orbiting several 'mature' stars bring new life to the question of just how common other planetary systems might be. Observations of very young stars provide a way to address this question and suggest that a significant number of such stars harbour conditions appropriate for the formation of planetary systems like our own.", "doi": "10.1038/383139a0", "issn": "0028-0836", "publisher": "Nature Publishing Group", "publication": "Nature", "publication_date": "1996-09-12", "series_number": "6596", "volume": "383", "issue": "6596", "pages": "139-144" }, { "id": "authors:g5ahj-82b15", "collection": "authors", "collection_id": "g5ahj-82b15", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20210125-153052077", "type": "book_section", "title": "Disk observations", "book_title": "Disks and Outflows Around Young Stars", "author": [ { "family_name": "Sargent", "given_name": "Anneila I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" } ], "contributor": [ { "family_name": "Beckwith", "given_name": "Steven V. W.", "clpid": "Beckwith-Steven-V-W" }, { "family_name": "Staude", "given_name": "Jakob", "clpid": "Staude-Jakob" }, { "family_name": "Quetz", "given_name": "Axel", "clpid": "Quetz-Axel" }, { "family_name": "Natta", "given_name": "Antonella", "clpid": "Natta-Antonella" } ], "abstract": "A wide variety of observations suggest that solar mass stars are surrounded by disks of gas and dust for much of their pre-main sequence lifetimes and even beyond. Here, techniques by which the small-scale circumstellar material can be detected are described and evidence for disks is briefly reviewed. Because of the general similarity between the disks around solar-mass stars and the nebula that surrounded the sun as the planets formed, disk properties may have strong bearing on our understanding of solar system evolution. Questions which must be addressed include: How frequently are disks found, and does the fraction vary with environment? What effect do companion stars have? How do disks evolve? Are low infrared fluxes necessarily indicative of disk clearing? Is there evidence of chemical evolution? How long do the disks persist? Are dissipation time-scales different for the gas and dust components? Observations addressing such problems will be summarized and discussed.", "doi": "10.1007/BFb0102623", "isbn": "978-3-540-61389-3", "publisher": "Springer", "place_of_publication": "Berlin", "publication_date": "1996", "pages": "1-23" }, { "id": "authors:1tr1t-aqc73", "collection": "authors", "collection_id": "1tr1t-aqc73", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190507-084119058", "type": "article", "title": "Aperture Synthesis Imaging of the Circumstellar Dust Disk around DO Tauri", "author": [ { "family_name": "Koerner", "given_name": "D. W.", "clpid": "Koerner-D-W" }, { "family_name": "Chandler", "given_name": "C. J.", "clpid": "Chandler-C-J" }, { "family_name": "Sargent", "given_name": "A. I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" } ], "abstract": "We have detected the T Tauri star, DO Tauri, in a 0 6 resolution VLA map of 43.3 GHz (\u03bb = 7 mm) continuum emission. The 43 GHz flux density lies on the same power-law slope defined by 89-232 GHz measurements, F_\u03bd \u221d \u03bd^\u03b1 with index \u03b1 = 2.39 \u00b1 0.23, confirming that the 43.3 GHz emission is thermal radiation from circumstellar dust. Upper limits to the flux densities at 8.4 and 22.5 GHz constrain the contribution of free-free emission from a compact ionized wind to be less than 49%. The dust emissivity index, \u03b2, is 0.39 \u00b1 0.23 if the emission is optically thin. Fitting a model of a thin circumstellar disk to the observed spectral energy distribution gives \u03b2 = 0.6 \u00b1 0.3, consistent with the power-law derivation. Both values are substantially lower than is generally accepted for the interstellar medium, suggesting grain growth. Given the youth of DO Tau and the early evolutionary state of its circumstellar disk, this result implies that millimeter-size grains have already formed by the early T Tauri phase.", "doi": "10.1086/309705", "issn": "0004-637X", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal", "publication_date": "1995-10-10", "series_number": "1", "volume": "452", "issue": "1", "pages": "L69-L72" }, { "id": "authors:3vbvt-j7q89", "collection": "authors", "collection_id": "3vbvt-j7q89", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120913-105433053", "type": "article", "title": "The FU Orionis binary system RNO 1B/1C", "author": [ { "family_name": "McMuldroch", "given_name": "Stuart", "clpid": "McMuldroch-S" }, { "family_name": "Blake", "given_name": "Geoffrey A.", "orcid": "0000-0003-0787-1610", "clpid": "Blake-G-A" }, { "family_name": "Sargent", "given_name": "Anneila I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" } ], "abstract": "Observations of CS (7\u21926) emission reveal a \u22653M_\u2299 core, 1.8\u00d710^4 AU in size, surrounding the FU Orionis binary system RNO 1B/1C. Fractional chemical abundances, calculated from LVG and LTE codes, are mostly similar to those in the cold core TMC 1. However, values for Si0/H_2 and CH_(3)0H/H_2 are enhanced, possibly by sputtering reactions or grain-grain collisions in tile outflow associated with the young stars. Aperture syntllesis maps of tile 2.6 and 3.1 mm continuum emission at ~5\" and ~9\" resolution, respectively, reveal that RNO 1C is surrounded by a flattened, dusty envelope, ~5000 AU in size, with mass\n\u22651.1 M_\u2299. High spatial resolution (~3\") interferometer observations of CS (2\u21921) emission may trace the dense walls of ail outflow cavity comprised of two concentric arcs with dynamical ages of 4\u00d710^3 and 1\u00d710^4 yr. The velocity structure of lower density gas imaged in the CO (1\u21920) transition is consistent with the arcs being formed by two energetic FU Orionis outbursts. Each event may have imparted more than 4 M_\u2299km s^(-1) to the outflow, implying outburst mass loss rates of ~10^(-4) M_\u2299 yr^(-1). It appears that RNO 1C is probably the driving source for the outflow and tllat, while pre-main sequence stars are in tile FU Orionis stage, outbursts may dominate both outflow morphology and energetics.", "issn": "0004-6256", "publisher": "American Astronomical Society", "publication": "Astronomical Journal", "publication_date": "1995-07", "series_number": "1", "volume": "110", "issue": "1", "pages": "354-365" }, { "id": "authors:dsckz-ska51", "collection": "authors", "collection_id": "dsckz-ska51", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160608-184750116", "type": "article", "title": "Imaging the Small-Scale Circumstellar Gas Around T Tauri Stars", "author": [ { "family_name": "Koerner", "given_name": "D. W.", "clpid": "Koerner-D-W" }, { "family_name": "Sargent", "given_name": "A. I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" } ], "abstract": "We have detected circumstellar molecular gas around a small sample of T Tauri stars through aperture synthesis imaging of CO(2\u21921) emission at \u02dc2\"-3\" resolution. RY Tauri, DL Tauri, DO Tauri, and AS 209 show resolved and elongated gaseous emission. For RY Tau, the deconvolved, half-maximum radius along the direction of elongation, P.A. \u02dc48\u00b0, is 110 AU. Corresponding radii and orientations for the other sources are: DL Tau-250 AU at P.A. \u02dc84\u00b0; DO Tau-350 AU at P.A. \u02dc160\u00b0; AS 209-290 AU at P.A. \u02dc138\u00b0. RY Tau, DL Tau, and AS 209 show velocity gradients parallel to the elongation, suggesting that the circumstellar material is rotating. RY Tan and AS 209 also exhibit double-peaked spectra characteristic of a rotating disk. Line emission from DO Tan is dominated by high-velocity blue shifted gas which complicates the interpretation. Nevertheless, there is in each case sufficient evidence to speculate that the circumstellar emission may arise from a protoplanetary disk similar to that from which our solar system formed.", "doi": "10.1086/117439", "issn": "1538-3881", "publisher": "American Astronomical Society", "publication": "Astronomical Journal", "publication_date": "1995-05", "series_number": "5", "volume": "109", "issue": "5", "pages": "2138-2145" }, { "id": "authors:2y1r2-82q72", "collection": "authors", "collection_id": "2y1r2-82q72", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20181121-083143567", "type": "book_section", "title": "The Owens Valley Millimeter Array", "book_title": "Astronomy with Millimeter and Submillimeter Wave Interferometry", "author": [ { "family_name": "Scoville", "given_name": "N.", "orcid": "0000-0002-0438-3323", "clpid": "Scoville-N-Z" }, { "family_name": "Carlstrom", "given_name": "J.", "orcid": "0000-0002-2044-7665", "clpid": "Carlstrom-J-E" }, { "family_name": "Padin", "given_name": "S.", "clpid": "Padin-S" }, { "family_name": "Sargent", "given_name": "A.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Scott", "given_name": "S.", "clpid": "Scott-S" }, { "family_name": "Woody", "given_name": "D.", "clpid": "Woody-D-P" } ], "contributor": [ { "family_name": "Ishiguro", "given_name": "M.", "clpid": "Ishiguro-M" }, { "family_name": "Welch", "given_name": "Wm. J.", "clpid": "Welch-Wm-J" } ], "abstract": "The present status and projected two year developments for the Owens Valley Millimeter Array are described and a brief summary of the astronomical research is presented.", "doi": "10.1017/S0252921100019023", "isbn": "9780937707784", "publisher": "Astronomical Society of the Pacific", "place_of_publication": "San Francisco, CA", "publication_date": "1994", "pages": "10-17" }, { "id": "authors:rkxte-52s43", "collection": "authors", "collection_id": "rkxte-52s43", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120919-133037673", "type": "article", "title": "The circumstellar environment of the FU Orionis pre-outburst candidate V1331 Cygni", "author": [ { "family_name": "McMuldroch", "given_name": "Stuart", "clpid": "McMuldroch-S" }, { "family_name": "Sargent", "given_name": "Anneila I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Blake", "given_name": "Geoffrey A.", "orcid": "0000-0003-0787-1610", "clpid": "Blake-G-A" } ], "abstract": "High resolution (~4\") aperture synthesis maps of the CO (1\u2192 0), ^(13)CO (1\u21920), ^(13)CO (2\u21921), and asociated continuum emission from the FU Orions candidate V1331 Cygni reveal a massive, 0.5 \u00b1 0.15 M_\u2609, circumstellar disk surrounded by a flattened gaseous envelope, 6000 x 4400 AU in size, mass >0.32 M_\u2609. These images and lower resolution measurements also trace a bipolar outflow and gaseous ring, 4.1 by 2.8 x 10^4 AU, mass greater than or equal to 0.07 M_\u2609, radially expanding at 22 \u00b1 4 kms^(-1). We suggest this ring is a swept-up gaseous torus from an energetic mass ejection stage, possibly an FU Orionis outburst or outburts, ~4 x 10^3 yr ago that imparted >10^(45) ergs into the ambient cloud.", "doi": "10.1086/116815", "issn": "0004-6256", "publisher": "American Astronomical Society", "publication": "Astronomical Journal", "publication_date": "1993-12", "series_number": "6", "volume": "106", "issue": "6", "pages": "2477-2485" }, { "id": "authors:9h415-ybf11", "collection": "authors", "collection_id": "9h415-ybf11", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161026-104538995", "type": "article", "title": "Millimeter and Submillimeter Interferometry of Astronomical Sources", "author": [ { "family_name": "Sargent", "given_name": "A. I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Welch", "given_name": "W. J.", "clpid": "Welch-W-J" } ], "abstract": "The development of millimeter and submillimeter interferometers was\nbasically motivated by the discovery, in the late 1960s and early 1970s,\nthat trace amounts of molecular gas in the interstellar medium could be\ndetected through millimeter-wave spectral line emission (cf Rank et al\n1971). The observed lines reflected the presence of unexpectedly large\namounts of molecular hydrogen, H_2 organized into giant molecular clouds\nwhere star formation takes place in the Milky Way and in other galaxies\n(e.g. Sanders et aI 1984). A wide variety of millimeter-wave molecular lines\nhave also been identified in the circumstellar shells around evolved stars\n(cf Loup et al 1993). The intensities and Doppler shifts of these mm-wave\nspectral lines provide information about the density, temperature,\nkinematics, and chemical state of the gas. In addition, interstellar and\ncircumstellar dust can be studied through observations of millimeter-wave continuum radiation. The success of centimeter-wavelength interferometers\nsuch as the VLA in producing fundamental new science argued\nthat millimeter-wavelength astronomy would also benefit from the high\nangular resolution provided by interferometers.", "doi": "10.1146/annurev.aa.31.090193.001501", "issn": "0066-4146", "publisher": "Annual Reviews", "publication": "Annual Review of Astronomy and Astrophysics", "publication_date": "1993-09", "volume": "31", "pages": "297-343" }, { "id": "authors:9tnwh-geq79", "collection": "authors", "collection_id": "9tnwh-geq79", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120912-091623177", "type": "article", "title": "Chemistry in circumstellar disks: CS toward HL Tauri", "author": [ { "family_name": "Blake", "given_name": "Geoffrey A.", "orcid": "0000-0003-0787-1610", "clpid": "Blake-G-A" }, { "family_name": "van Dishoeck", "given_name": "Ewine F.", "orcid": "0000-0001-7591-1907", "clpid": "van-Dishoeck-E-F" }, { "family_name": "Sargent", "given_name": "Anneila I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" } ], "abstract": "High-resolution millimeter-wave aperture synthesis images of the CS J = 2 \u2192 1 and dust continuum emission\ntoward the young star HL Tauri have been combined with single-dish spectra of the higher J CS transitions\nin order to probe the chemical and physical structure of circumstellar material in this source. We find that the\nextended molecular cloud surrounding HL Tau is similar to other Taurus dark cloud cores, having T_(kinetic) \u2248 \n10-20 K, n_(H2) \u2248 10^4-10^5 cm^(-3) , and x(CS) = N(CS)/N(H_2) \u2248 (1-2) x 10^(-8). In contrast, the gas-phase CS abundance in the circumstellar disk is depleted by factors of at least 25-50, and perhaps considerably more. These results are consistent with substantial depletion onto grains, or a transition from kinetically controlled chemistry in the molecular cloud to thermodynamically controlled chemistry in the outer regions of the circumstellar disk. Dust continuum emission at 3.06 mm, although unresolved in a 3\".0 beam, appears centered on the stellar position; combined with other millimeter-wave measurements its intensity indicates an emissivity index of\n\u03b2 = 1.2 \u00b1 0.3. This \u03b2 may reflect grain growth via depletion and aggregation or compositional evolution, and\nsuggests that the 3.06 mm dust opacity exceeds unity within 8-10 AU of HL Tauri. Even at millimeter and\nsubmillimeter wavelengths, observational studies of other high dipole moment molecules in circumstellar disks\nmay also be hampered by the combination of grain mantle depletion and dust opacity structure in sources viewed nearly edge-on.", "doi": "10.1086/186407", "issn": "0004-637X", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal", "publication_date": "1992-06-01", "series_number": "2", "volume": "391", "issue": "2", "pages": "L99-L103" }, { "id": "authors:rrw24-bnd69", "collection": "authors", "collection_id": "rrw24-bnd69", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120917-134214669", "type": "article", "title": "IRAS 16293-2422: A very young binary system?", "author": [ { "family_name": "Mundy", "given_name": "Lee G.", "clpid": "Mundy-L-G" }, { "family_name": "Wooten", "given_name": "Alwyn", "clpid": "Wooten-A" }, { "family_name": "Wilking", "given_name": "Bruce A.", "clpid": "Wilking-B-A" }, { "family_name": "Blake", "given_name": "Geoffrey A.", "orcid": "0000-0003-0787-1610", "clpid": "Blake-G-A" }, { "family_name": "Sargent", "given_name": "Anneila I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" } ], "abstract": "We present 4\".5 x 2\".5 resolution millimeter wavelength observations of the young far-infrared source IRAS\n16293-2422 which resolve the continuum emission into two sources, MM 1 and MM 2. These sources coincide with known radio continuum sources and may constitute a very young binary system with a projected separation of 840 AU. Flux measurements from 18 cm to 25 \u03bcm show that the majority of the millimeter wavelength emission arises from dust within 300 AU of the individual central objects. The total dynamical mass of 1.1-1.3 M_\u2299, coupled with our mass estimates for MM 1 and MM 2, suggests that the mass in circumstellar material is comparable to that of the central stellar cores. Since the stellar masses are constrained to be \u2264 0.5 M_\u2299 each, it is likely that the bolometric luminosity of 30-40 L_\u2299 is derived mainly from accretion of the observed circumstellar material. Maps of the J = 2, 3-1, 2 transition of SO obtained simultaneously show that this emission is centered on MM 1, with weaker emission in a clumpy distribution to the east and west. No SO emission is detected toward MM 2, indicating an upper limit to the fractional abundance which is a factor of 10 below that toward MM 1. We propose that the SO emission toward MM 1 is a result of the outflow activity associated with this source and that the outlying emission clumps trace regions of mild interaction between the outflow and the ambient cloud.", "doi": "10.1086/170939", "issn": "0004-637X", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal", "publication_date": "1992-01-20", "series_number": "1", "volume": "385", "issue": "1", "pages": "306-313" }, { "id": "authors:4tc2g-1my70", "collection": "authors", "collection_id": "4tc2g-1my70", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20181211-093131094", "type": "book_section", "title": "Arp 299 - Two Interacting Galaxies", "book_title": "Dynamics of Galaxies and their Molecular Cloud Distributions", "author": [ { "family_name": "Sargent", "given_name": "A. I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Scoville", "given_name": "N. Z.", "orcid": "0000-0002-0438-3323", "clpid": "Scoville-N-Z" }, { "family_name": "Sanders", "given_name": "D. B.", "orcid": "0000-0002-1233-9998", "clpid": "Sanders-D-B" } ], "contributor": [ { "family_name": "Combes", "given_name": "F.", "clpid": "Combes-F" }, { "family_name": "Casoli", "given_name": "Fabienne", "clpid": "Casoli-F" } ], "abstract": "Arp 299 (Mrk 171), is an interacting system at 42 Mpc, comprising the galaxies IC 694 and NGC 3690. Interferometric CO maps at 6\u2033 resolution (Sargent et al. 1987) showed compact molecular condensations at the nucleus of IC694 and in the overlap region of the galaxy disks [positions A and C \u2013 C in the terminology of Gehrz, Sramek, and Weedman (1983)].", "doi": "10.1017/S0074180900244768", "isbn": "9780792310969", "publisher": "Kluwer", "place_of_publication": "Dordrecht", "publication_date": "1991", "pages": "430" }, { "id": "authors:fba02-bnp76", "collection": "authors", "collection_id": "fba02-bnp76", "cite_using_url": "https://authors.library.caltech.edu/records/fba02-bnp76", "type": "book_section", "title": "Results from 1.4 Millimeter Wavelength Interferometry at the Owens Valley", "book_title": "Submillimetre Astronomy", "author": [ { "family_name": "Mundy", "given_name": "L. G.", "orcid": "0000-0002-8876-0690" }, { "family_name": "Sargent", "given_name": "A. I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Scoville", "given_name": "N. Z.", "orcid": "0000-0002-0438-3323", "clpid": "Scoville-N-Z" }, { "family_name": "Padin", "given_name": "S.", "orcid": "0009-0001-9993-4393", "clpid": "Padin-Stephen" }, { "family_name": "Woody", "given_name": "D. P.", "orcid": "0000-0003-1734-2472", "clpid": "Woody-D-P" } ], "abstract": "
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This paper summarizes the first interferometric results in the 1.4 mm band from the Owens Valley Radio Observatory (OVRO) Millimeter Wave Array. Relative to 2.7 mm, observations of thermal dust and molecular emission at 1.4 mm benefit from increased emissivity and brightness temperature sensitivity. For optically thin emir ion in the Rayleigh-Jeans limit, dust emission increases as λ3 to λ-4 assuming λ-1 to λ-2 wavelength dependence for the dust emissivity, while molecular emission increases faster than λ-2 due to the Planck function and the larger statistical weights of higher levels. In the optically thick limit, both increase as λ-2. This λ-2 advantage can also be expressed in terms of the brightness temperature sensitivity; for a given beam size, the rms brightness temperature corresponding to a specific rms flux level is a factor of 4 lower for the 1.4 mm band than for the 2.7 mm band.

\n
\n
", "doi": "10.1007/978-94-015-6850-0_54", "issn": "0067-0057", "isbn": "978-94-015-6852-4", "publisher": "Springer Netherlands", "place_of_publication": "Dordrecht", "publication": "Astrophysics and Space Science Library", "publication_date": "1990-01-31", "volume": "158", "pages": "155-156" }, { "id": "authors:b4vqb-ebx03", "collection": "authors", "collection_id": "b4vqb-ebx03", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20210217-195625774", "type": "book_section", "title": "CO (2-1) Studies of Centaurus A", "book_title": "Submillimetre Astronomy", "author": [ { "family_name": "Phillips", "given_name": "T. G.", "clpid": "Phillips-T-G" }, { "family_name": "Sanders", "given_name": "D. B.", "orcid": "0000-0002-1233-9998", "clpid": "Sanders-David-B" }, { "family_name": "Sargent", "given_name": "A. I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" } ], "contributor": [ { "family_name": "Watt", "given_name": "Graeme D.", "clpid": "Watt-Graeme-D" }, { "family_name": "Webster", "given_name": "Adrian S.", "clpid": "Webster-Adrian-S" } ], "abstract": "Using the Caltech Submillimeter Observatory (CSO), Phillips et al. (1987) detected CO emission from the nearby radio galaxy Centaurus A. They reported emission from the dust lane region and showed that the material rotated very much like a disk galaxy imbedded within the larger elliptical system. They also showed that the heliocentric systemic velocity revealed by the CO observations at 547 (\u00b1 5) km/s was close to the value of 538 (\u00b1 10) km/s found for the elliptical component by Wilkinson et al. (1986).", "doi": "10.1007/978-94-015-6850-0_83", "isbn": "9789401568524", "publisher": "Springer Netherlands", "place_of_publication": "Dordrecht", "publication_date": "1990", "pages": "223-224" }, { "id": "authors:6cvnd-2pt87", "collection": "authors", "collection_id": "6cvnd-2pt87", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20210217-195625533", "type": "book_section", "title": "CO(2\u21921) / CO(1\u21920) observations of luminous infrared galaxies", "book_title": "Submillimetre Astronomy", "author": [ { "family_name": "Sanders", "given_name": "D. B.", "orcid": "0000-0002-1233-9998", "clpid": "Sanders-David-B" }, { "family_name": "Sargent", "given_name": "A. I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Scoville", "given_name": "N. Z.", "orcid": "0000-0002-0438-3323", "clpid": "Scoville-N-Z" }, { "family_name": "Phillips", "given_name": "T. G.", "clpid": "Phillips-T-G" } ], "contributor": [ { "family_name": "Watt", "given_name": "Graeme D.", "clpid": "Watt-Graeme-D" }, { "family_name": "Webster", "given_name": "Adrian S.", "clpid": "Webster-Adrian-S" } ], "abstract": "CO(2\u21921) spectra of several luminous infrared galaxies have been obtained with the Caltech Submillimeter Observatory (CSO). For those galaxies distant enough to be unresolved with the CSO beam, we have compared the CO(2\u21921) profile with the corresponding, unresolved CO(1\u21920) profile in order to investigate the contribution of optically thin CO to the total CO emission.", "doi": "10.1007/978-94-015-6850-0_78", "isbn": "9789401568524", "publisher": "Springer Netherlands", "place_of_publication": "Dordrecht", "publication_date": "1990", "pages": "213-214" }, { "id": "authors:4bfs4-ksv34", "collection": "authors", "collection_id": "4bfs4-ksv34", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20201008-112316591", "type": "book_section", "title": "CO(2\u21921) Emission from NGC 3256: An Interacting Pair of Galaxies", "book_title": "Submillimetre Astronomy", "author": [ { "family_name": "Sargent", "given_name": "A. I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Sanders", "given_name": "D. B.", "orcid": "0000-0002-1233-9998", "clpid": "Sanders-D-B" }, { "family_name": "Phillips", "given_name": "T. G.", "clpid": "Phillips-T-G" } ], "contributor": [ { "family_name": "Watt", "given_name": "Graeme D.", "clpid": "Watt-G-D" }, { "family_name": "Webster", "given_name": "Adrian S.", "clpid": "Webster-A-S" } ], "abstract": "At optical wavelengths, characteristic \"tails\" and chaotic nuclear appearance clearly identify NGC 3256 as an interacting system (Toomre 1977; Schweizer 1986). The newly-constructed, 10.4 m diameter, Leighton telescope of the Caltech Submillimeter Observatory (CSO) has been used to acquire observations of this merger in the CO (2\u21921) transition at 230 GHz. The turbulent nature of NGC 3256 is immediately obvious in Figure 1, a high contrast photograph provided by F. Schweizer, where circles representing the beam (30\u2033 FWHM) indicate the positions observed.", "doi": "10.1007/978-94-015-6850-0_82", "isbn": "9789401568524", "publisher": "Springer Netherlands", "place_of_publication": "Dordrecht", "publication_date": "1990", "pages": "221-222" }, { "id": "authors:ccsvc-vb687", "collection": "authors", "collection_id": "ccsvc-vb687", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20181120-134410139", "type": "article", "title": "Recent CO(2-1) Observations of Galaxies with the CSO", "author": [ { "family_name": "Sargent", "given_name": "A. I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Phillips", "given_name": "T. G.", "clpid": "Phillips-T-G" }, { "family_name": "Sanders", "given_name": "D. B.", "orcid": "0000-0002-1233-9998", "clpid": "Sanders-D-B" }, { "family_name": "Scoville", "given_name": "N.", "orcid": "0000-0002-0438-3323", "clpid": "Scoville-N-Z" } ], "abstract": "CO(2\u21921) observations of a number of galaxies have recently been obtained with the CSO. Examples are presented here to illustrate the capabilities of the instrument.", "doi": "10.1017/S1539299600008479", "issn": "1539-2996", "publisher": "Kluwer Academic Publishers", "publication": "Highlights of Astronomy", "publication_date": "1989", "volume": "8", "pages": "591-592" }, { "id": "authors:th7f6-qmp59", "collection": "authors", "collection_id": "th7f6-qmp59", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20181121-090050084", "type": "book_section", "title": "Molecular Disks Around Young Stars", "book_title": "Structure and Dynamics of the Interstellar Medium", "author": [ { "family_name": "Sargent", "given_name": "Anneila I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Beckwith", "given_name": "Steven V. W.", "clpid": "Beckwith-S-V-W" } ], "contributor": [ { "family_name": "Moles", "given_name": "Mariano", "clpid": "Moles-M" }, { "family_name": "Tenorio-Tagle", "given_name": "Guillermo", "clpid": "Tenorio-Tagle-G" }, { "family_name": "Melnick", "given_name": "Jorge", "clpid": "Melnick-J" } ], "abstract": "There is now a substantial body of evidence that disk-like structures of gas and dust surround many protostars and young stellar objects (e.g. Rodriguez, these proceedings). We are currently studying a number of these disks to establish whether they have properties compatible with those attributed to the proto-solar nebula, in the early stages of evolution of our solar system. The frequency with which such proto-planetary disks are associated with young stars is also being investigated.", "doi": "10.1017/S0252921100023769", "isbn": "9783540519560", "publisher": "Springer", "place_of_publication": "Berlin", "publication_date": "1989", "pages": "215-220" }, { "id": "authors:e5ks6-zp582", "collection": "authors", "collection_id": "e5ks6-zp582", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20181119-130439078", "type": "book_section", "title": "High Resolution Studies of Star-Forming Molecular Clouds", "book_title": "Star Forming Regions", "author": [ { "family_name": "Sargent", "given_name": "A. I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Scoville", "given_name": "N.", "orcid": "0000-0002-0438-3323", "clpid": "Scoville-N-Z" }, { "family_name": "Masson", "given_name": "C. R.", "clpid": "Masson-C-R" }, { "family_name": "Lo", "given_name": "K. Y.", "clpid": "Lo-K-Y" }, { "family_name": "Phillips", "given_name": "T. G.", "clpid": "Phillips-T-G" } ], "contributor": [ { "family_name": "Jugaku", "given_name": "Jun", "clpid": "Jugaku-Jun" }, { "family_name": "Peimbert", "given_name": "Manuel", "clpid": "Peimbert-M" } ], "abstract": "Observations of star formation sites in a number of molecular clouds, including NGC 7538, NGC 2071, Cepheus A and K3-50A, have been made using the Owens Valley millimeter wave interferometer. The measurements of ^(12)CO, ^(13)CO, CS and continuum emission are at resolutions of order 7\u2033. Continuum emission at 2.7 mm is detected from all the cloud cores and, in general, the ^(12)CO interferometer maps reveal the presence of high velocity, bipolar outflows within 10\u2033 of these continuum sources. Thus, the origins of the outflows are readily identifiable; the flows themselves appear to remain collimated on scales of less than 10^(17) cm. The orientations of the flows are similar to those seen at lower resolution, except in Cepheus A, where the interferometer is capable of distinguishing between two outflows which are confused in single telescope maps.", "doi": "10.1017/S0074180900095693", "isbn": "9789027723888", "publisher": "D. Reidel", "place_of_publication": "Dordrecht", "publication_date": "1987", "pages": "329-330" }, { "id": "authors:3vrhy-n7y56", "collection": "authors", "collection_id": "3vrhy-n7y56", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20201014-153714184", "type": "book_section", "title": "Structure of Star-Forming Regions-The Ages of Subgroups and the Progression of Star Formation", "book_title": "Birth and Evolution of Massive Stars and Stellar Groups", "author": [ { "family_name": "Sargent", "given_name": "Anneila I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" } ], "contributor": [ { "family_name": "Boland", "given_name": "Wilfried", "clpid": "Boland-W" }, { "family_name": "van Woerden", "given_name": "Hugo", "clpid": "van-Woerden-H" } ], "abstract": "The structure of star-forming regions is examined on scales ranging from the few hundred parsecs typical of OB-association/molecular-cloud complexes to the few hundredths of a parsec structure observed in dense cloud cores. Explanations of both the temporal and spatial progress of star formation are reviewed, and factors which may dominate the process on all scales are considered.", "doi": "10.1007/978-94-009-5478-6_2", "isbn": "9789401089197", "publisher": "Springer Netherlands", "place_of_publication": "Dordrecht", "publication_date": "1985", "pages": "5-22" }, { "id": "authors:vrtxy-czy95", "collection": "authors", "collection_id": "vrtxy-czy95", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20201001-145811098", "type": "book_section", "title": "Radio and Infrared Observations of OH/IR Stars", "book_title": "Mass Loss from Red Giants", "author": [ { "family_name": "Sargent", "given_name": "Anneila I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Baud", "given_name": "Boudewijn", "clpid": "Baud-Boudewijn" } ], "contributor": [ { "family_name": "Morris", "given_name": "Mark", "clpid": "Morris-Mark" }, { "family_name": "Zuckerman", "given_name": "Ben", "clpid": "Zuckerman-B" } ], "abstract": "Combined infrared and OH spectral line observations are essential to understanding the nature of OH/IR stars, the properties of their circumstellar envelopes and the OH maser pump mechanism. We have used the Very Large Array of the National Radio Astronomy Observatory to determine very precise radio positions for a selection of such objects near the tangential point and at the galactic center and have subsequently made simultaneous infrared and OH observations of both samples. From the infrared measurements, luminosities of these stars and masses of the thick dust shells which surround them have been derived, while the double-peaked OH emission line profiles have yielded both the stellar radial velocities, v_R, and the expansion velocities of the envelopes, v_e, as well as the maser luminosities. The selection criteria and the observations are described in detail elsewhere (Baud et al. 1984). The results are consistent with these stars lying at the top of the Asymptotic Giant Branch (AGB) of the Hertzsprung-Russell diagram; the dense circumstellar shells suggest that these objects are evolving rapidly through a phase of high mass loss.", "doi": "10.1007/978-94-009-5428-1_34", "isbn": "9789401088961", "publisher": "Springer Netherlands", "place_of_publication": "Dordrecht", "publication_date": "1985", "pages": "213-214" }, { "id": "authors:f5wak-t5b73", "collection": "authors", "collection_id": "f5wak-t5b73", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20181211-154717976", "type": "book_section", "title": "CO (2\u20131) observations of Maffei 2", "book_title": "The Milky Way Galaxy", "author": [ { "family_name": "Sargent", "given_name": "Anneila I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Sutton", "given_name": "E. C.", "clpid": "Sutton-E-C" }, { "family_name": "Masson", "given_name": "C. R.", "clpid": "Masson-C-R" }, { "family_name": "Phillips", "given_name": "T. G.", "clpid": "Phillips-T-G" }, { "family_name": "Lo", "given_name": "K.-Y.", "clpid": "Lo-K-Y" } ], "abstract": "Maffei 2 is a highly obscured galaxy, probably of type Sbc, at a distance of 5 Mpc (Allen and Raimond 1972; Spinrad et al. 1973). Since it lies close to the Galactic plane, there is considerable confusion in infrared and 21-cm HI observations due to Galactic emission, but investigations of its structure can be carried out at millimeter wavelengths where the Galaxy contribution is confined to a limited velocity range. The high resolution (30\u2033) of our CO J=2\u20131 observations permits both a detailed examination of Maffei 2 and a study of the nature of the gas in its nucleus, through comparison with the CO J=1\u20130 observations.", "doi": "10.1017/S0074180900242411", "isbn": "9789400952911", "publisher": "D. Reidel", "place_of_publication": "Dordrecht", "publication_date": "1985", "pages": "197-198" }, { "id": "authors:gnwqg-fd822", "collection": "authors", "collection_id": "gnwqg-fd822", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160421-164244322", "type": "book_section", "title": "Aperture Synthesis Maps of CO Emission from M51", "author": [ { "family_name": "Lo", "given_name": "K. Y.", "clpid": "Lo-K-Y" }, { "family_name": "Berge", "given_name": "G.", "clpid": "Berge-G-L" }, { "family_name": "Claussen", "given_name": "M.", "clpid": "Claussen-M-J" }, { "family_name": "Heiligman", "given_name": "G.", "clpid": "Heiligman-G-M" }, { "family_name": "Keene", "given_name": "J.", "clpid": "Keene-Jocelyn" }, { "family_name": "Masson", "given_name": "C.", "clpid": "Masson-C" }, { "family_name": "Phillips", "given_name": "T.", "clpid": "Phillips-T-G" }, { "family_name": "Sargent", "given_name": "A.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Scoville", "given_name": "N.", "orcid": "0000-0002-0438-3323", "clpid": "Scoville-N-Z" }, { "family_name": "Watson", "given_name": "D.", "clpid": "Watson-D" }, { "family_name": "Woody", "given_name": "D.", "clpid": "Woody-D-P" }, { "literal": "International Union of Radio Science" }, { "literal": "Instituto de Radioastronomia Milimetrica" } ], "abstract": "7\"-resolution maps of CO emission from the central 2' of M51 have been made with the Owens Valley millimeter-wave interferometer. Relative warm gas from giant molecular clouds is seen largely confined to arms coincident with the dust lanes, forming coherent structure on the scale of ~3 Kpc. There is a minimum of CO emission within 400 pc of the center. Integrated CO intensity maps are presented. Non-circular motion of the CO gas is evident from the velocity field.", "publisher": "International Union of Radio Science", "publication_date": "1984" }, { "id": "authors:vnsfy-t1r07", "collection": "authors", "collection_id": "vnsfy-t1r07", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160421-082902012", "type": "book_section", "title": "The Caltech Millimeter Wave Interferometer", "author": [ { "family_name": "Masson", "given_name": "C. R.", "clpid": "Masson-C-R" }, { "family_name": "Berge", "given_name": "G. L.", "clpid": "Berge-G-L" }, { "family_name": "Claussen", "given_name": "Mark J.", "clpid": "Claussen-M-J" }, { "family_name": "Heiligman", "given_name": "G. M.", "clpid": "Heiligman-G-M" }, { "family_name": "Leighton", "given_name": "R. B.", "clpid": "Leighton-R-B" }, { "family_name": "Lo", "given_name": "K. Y.", "clpid": "Lo-K-Y" }, { "family_name": "Moffett", "given_name": "A. T.", "clpid": "Moffett-A-T" }, { "family_name": "Phillips", "given_name": "T. G.", "clpid": "Phillips-T-G" }, { "family_name": "Sargent", "given_name": "Anneila I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" }, { "family_name": "Scott", "given_name": "S. L.", "clpid": "Scott-S-L" }, { "family_name": "Woody", "given_name": "David P.", "clpid": "Woody-D-P" }, { "family_name": "Young", "given_name": "A.", "clpid": "Young-A" }, { "literal": "International Union of Radio Science" }, { "literal": "Instituto de Radioastronomia Milimetrica" } ], "abstract": "The Caltech Millimeter-Wave Interferometer has recently begun observations at a wavelength of 2.6 mm. We describe the instrument and some of the first results from it.", "publisher": "International Union of Radio Science", "publication_date": "1984" }, { "id": "authors:eqdah-n1y70", "collection": "authors", "collection_id": "eqdah-n1y70", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190918-133847347", "type": "article", "title": "Molecular clouds and star formation. I - Observations of the Cepheus OB3 molecular cloud", "author": [ { "family_name": "Sargent", "given_name": "Anneila I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" } ], "abstract": "To determine the connection between newly formed stars and molecular clouds, observations were made in and around the young OB association Cepheus OB3 in the J = 1\u21920 transition of ^(12)CO. An extended (20 pc x 60 pc) molecular cloud was detected and mapped, and additional observations of ^(13)CO and H_2CO were made at selected positions. Moderately enhanced temperatures and densities were noted in several portions of the cloud. It appears that star formation is still continuing in the Cepheus OB3 complex.", "doi": "10.1086/155729", "issn": "0004-637X", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal", "publication_date": "1977-12-15", "series_number": "1", "volume": "218", "issue": "1", "pages": "736-748" }, { "id": "authors:7758v-f0g54", "collection": "authors", "collection_id": "7758v-f0g54", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190918-133847264", "type": "article", "title": "The Nature of Faint Blue Stars in the Halo. II", "author": [ { "family_name": "Greenstein", "given_name": "Jesse L.", "clpid": "Greenstein-J-L" }, { "family_name": "Sargent", "given_name": "Anneila I.", "orcid": "0000-0002-4633-5098", "clpid": "Sargent-A-I" } ], "abstract": "Spectra and colors of 189 hot (FB) stars selected colorimetrically and mostly within 30\u00b0 of the galactic poles are analyzed quantitatively for surface gravity and effective temperatures. Palomar spectra give line intensities and Balmer line profiles, found in the Appendix tables. Using a network of model atmospheres, the g and \u03b8 so determined give directly the light-to-mass ratio, and eventually the luminosities. The high-latitude hot stars cover a range of 10^6 in luminosity, and are classifiable into various groups. \n\nSpectroscopically normal B stars make up 26 percent of the sample; they rotate and have nearly normal line spectra. Interpreted as Population I stars, on the mass-luminosity relation, they have relatively high luminosities and large z-coordinates. For some, the nuclear lifetimes at present luminosities are less than transit times from the plane. Their high velocities present a problem for galactic kinematics. A few are slightly helium rich, while others are highly evolved Population II stars, from details of the spectroscopy. Some of the Population I stars may be in not-understood, short-lived evolutionary phases of high luminosity and low mass. \n\nThe (g, \u03b8)-relation can be transformed into luminosity-temperature diagrams if masses are known. Many fall along a relation log g\u03b8^4 = 2.35, have common properties of halo stars, and T_(eff) from 9500\u00b0 to 40,000\u00b0 K. The light-to-mass ratio for these is 68 (in solar units) ; most HB and sdB stars have weak metal and weak helium lines, i.e., are halo stars. We call this the extended horizontal branch (EHB). Quantitative classification gives 17 percent of the FB stars as horizontal-branch B and early A (HB) stars, and 16 percent subdwarf B (sdB) stars. There are 16 percent subdwarf O (sdO) stars, including planetary nuclei; these have strong, or very strong, helium lines. Assuming a constant mass, 0.66 m_\u2299, the observed L/m gives Mb = +0.5. The EHB for field stars fits the globular cluster HB, and extends it to high T_(eff). The bolometric correction produces the change of M_v with color. The hot white dwarfs are 11 percent of the FB stars and appear as a bridge between the sdO stars and the ordinary DA white dwarfs. Composite stars are unresolved, noninteracting binaries with strange UBV colors; they require a faint Mv for the primary (e.g., sdO or sdB), and an unevolved G companion. \n\nThe helium deficiency and the evolutionary problems are sharpest for the EHB stars. In a few, slightly stronger helium lines are accompanied by lines of peculiar elements (S III, P II seen at high dispersion. While the L/m ratio is closely the same for sdO as for sdB and HB, the He lines become strong. Evolutionary tracks avoid the region of the hot EHB stars; the hottest sdO stars approach the helium main sequence. The low surface helium is almost certainly not cosmological in origin. Gravitational diffusion in a nonrotating star in the absence of convection is plausible; in the sdO and the peculiar sdB stars convection and helium flashes may have occurred. \n\nNumerous radial velocities were measured. Where possible, proper motions, luminosities, and radial-velocity dispersions were used for space motions. The Population I normal stars have abnormally high space motions, not greatly different from Population II stars. The luminosities derived from spectroscopy are consistent with those from peculiar motions.", "doi": "10.1086/190315", "issn": "0067-0049", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal Supplement Series", "publication_date": "1974-11", "series_number": "259", "volume": "28", "issue": "259", "pages": "157-209" } ]