[ { "id": "authors:v8nsc-tes31", "collection": "authors", "collection_id": "v8nsc-tes31", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20220808-886879000", "type": "article", "title": "The long-active afterglow of GRB 210204A: detection of the most delayed flares in a gamma-ray burst", "author": [ { "family_name": "Kumar", "given_name": "Harsh", "orcid": "0000-0003-0871-4641", "clpid": "Kumar-Harsh" }, { "family_name": "Gupta", "given_name": "Rahul", "clpid": "Gupta-Rahul" }, { "family_name": "Saraogi", "given_name": "Divita", "clpid": "Saraogi-Divita" }, { "family_name": "Ahumada", "given_name": "Tom\u00e1s", "orcid": "0000-0002-2184-6430", "clpid": "Ahumada-Tom\u00e1s" }, { "family_name": "Andreoni", "given_name": "Igor", "orcid": "0000-0002-8977-1498", "clpid": "Andreoni-Igor" }, { "family_name": "Anupama", "given_name": "G. C.", "orcid": "0000-0003-3533-7183", "clpid": "Anupama-Gadiyara-Chakrapani" }, { "family_name": "Aryan", "given_name": "Amar", "orcid": "0000-0002-9928-0369", "clpid": "Aryan-Amar" }, { "family_name": "Barway", "given_name": "Sudhanshu", "orcid": "0000-0002-3927-5402", "clpid": "Barway-Sudhanshu" }, { "family_name": "Bhalerao", "given_name": "Varun", "orcid": "0000-0002-6112-7609", "clpid": "Bhalerao-Varun-B" }, { "family_name": "Chandra", "given_name": "Poonam", "orcid": "0000-0002-0844-6563", "clpid": "Chandra-Poonam" }, { "family_name": "Coughlin", "given_name": "Michael W.", "orcid": "0000-0002-8262-2924", "clpid": "Coughlin-Michael-W" }, { "family_name": "Dimple", "given_name": "[None]", "clpid": "Dimple-" }, { "family_name": "Dutta", "given_name": "Anirban", "orcid": "0000-0002-7708-3831", "clpid": "Dutta-Anirban" }, { "family_name": "Ghosh", "given_name": "Ankur", "clpid": "Ghosh-Ankur" }, { "family_name": "Ho", "given_name": "Anna Y. Q.", "orcid": "0000-0002-9017-3567", "clpid": "Ho-Anna-Y-Q" }, { "family_name": "Kool", "given_name": "E. C.", "orcid": "0000-0002-7252-3877", "clpid": "Kool-Erik-C" }, { "family_name": "Kumar", "given_name": "Amit", "clpid": "Kumar-Amit" }, { "family_name": "Medford", "given_name": "Michael S.", "orcid": "0000-0002-7226-0659", "clpid": "Medford-Michael-S" }, { "family_name": "Misra", "given_name": "Kuntal", "orcid": "0000-0003-1637-267X", "clpid": "Misra-Kuntal" }, { "family_name": "Pandey", "given_name": "Shashi B.", "clpid": "Pandey-Shashi-Bhushan" }, { "family_name": "Perley", "given_name": "Daniel A.", "orcid": "0000-0001-8472-1996", "clpid": "Perley-Daniel-A" }, { "family_name": "Riddle", "given_name": "Reed", "orcid": "0000-0002-0387-370X", "clpid": "Riddle-Reed-L" }, { "family_name": "Ror", "given_name": "Amit Kumar", "clpid": "Ror-Amit-Kumar" }, { "family_name": "Setiadi", "given_name": "Jason M.", "clpid": "Setiadi-Jason-M" }, { "family_name": "Yao", "given_name": "Yuhan", "orcid": "0000-0001-6747-8509", "clpid": "Yao-Yuhan" } ], "abstract": "We present results from extensive broadband follow-up of GRB 210204A over the period of 30 d. We detect optical flares in the afterglow at 7.6 \u00d7 10\u2075 s and 1.1 \u00d7 10\u2076 s after the burst: the most delayed flaring ever detected in a GRB afterglow. At the source redshift of 0.876, the rest-frame delay is 5.8 \u00d7 10\u2075 s (6.71 d). We investigate possible causes for this flaring and conclude that the most likely cause is a refreshed shock in the jet. The prompt emission of the GRB is within the range of typical long bursts: it shows three disjoint emission episodes, which all follow the typical GRB correlations. This suggests that GRB 210204A might not have any special properties that caused late-time flaring, and the lack of such detections for other afterglows might be resulting from the paucity of late-time observations. Systematic late-time follow-up of a larger sample of GRBs can shed more light on such afterglow behaviour. Further analysis of the GRB 210204A shows that the late-time bump in the light curve is highly unlikely due to underlying SNe at redshift (z) = 0.876 and is more likely due to the late-time flaring activity. The cause of this variability is not clearly quantifiable due to the lack of multiband data at late-time constraints by bad weather conditions. The flare of GRB 210204A is the latest flare detected to date.", "doi": "10.1093/mnras/stac1061", "issn": "0035-8711", "publisher": "Royal Astronomical Society", "publication": "Monthly Notices of the Royal Astronomical Society", "publication_date": "2022-06", "series_number": "2", "volume": "513", "issue": "2", "pages": "2777-2793" }, { "id": "authors:n5m70-jjt30", "collection": "authors", "collection_id": "n5m70-jjt30", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20201209-113403455", "type": "article", "title": "The search for fast transients with CZTI", "author": [ { "family_name": "Sharma", "given_name": "Y.", "orcid": "0000-0003-4531-1745", "clpid": "Sharma-Yashvi" }, { "family_name": "Marathe", "given_name": "A.", "orcid": "0000-0002-8869-8137", "clpid": "Marathe-Aditi" }, { "family_name": "Bhalerao", "given_name": "V.", "orcid": "0000-0002-6112-7609", "clpid": "Bhalerao-Varun-B" }, { "family_name": "Shenoy", "given_name": "V.", "orcid": "0000-0002-6429-8139", "clpid": "Shenoy-Vedant" }, { "family_name": "Waratkar", "given_name": "G.", "orcid": "0000-0003-3630-9440", "clpid": "Waratkar-Gaurav" }, { "family_name": "Nadella", "given_name": "D.", "orcid": "0000-0003-4942-6873", "clpid": "Nadella-Drishika" }, { "family_name": "Page", "given_name": "P.", "orcid": "0000-0002-8239-9670", "clpid": "Page-Pranav" }, { "family_name": "Hebbar", "given_name": "P.", "orcid": "0000-0002-4961-4690", "clpid": "Hebbar-Pavan-R" }, { "family_name": "Vibhute", "given_name": "A.", "orcid": "0000-0003-1501-6972", "clpid": "Vibhute-Ajay" }, { "family_name": "Bhattacharya", "given_name": "D.", "orcid": "0000-0003-3352-3142", "clpid": "Bhattacharya-Dipankar" }, { "family_name": "Rao", "given_name": "A. R.", "orcid": "0000-0003-0833-0533", "clpid": "Rao-A-R" }, { "family_name": "Vadawale", "given_name": "S.", "orcid": "0000-0002-2050-0913", "clpid": "Vadawale-Santosh-V" } ], "abstract": "The Cadmium\u2013Zinc\u2013Telluride Imager on AstroSat has proven to be a very effective All-Sky monitor in the hard X-ray regime, detecting over three hundred GRBs and putting highly competitive upper limits on X-ray emissions from gravitational wave sources and fast radio bursts. We present the algorithms used for searching for such transient sources in CZTI data, and for calculating upper limits in case of non-detections. We introduce CIFT: the CZTI Interface for Fast Transients, a framework used to streamline these processes. We present details of 87 new GRBs detected by this framework that were previously not detected in CZTI.", "doi": "10.1007/s12036-021-09714-6", "issn": "0250-6335", "publisher": "Springer", "publication": "Journal of Astrophysics and Astronomy", "publication_date": "2021-10", "series_number": "2", "volume": "42", "issue": "2", "pages": "Art. No. 73" } ]