CaltechAUTHORS: Combined
https://feeds.library.caltech.edu/people/Lyons-T-T/combined.rss
A Caltech Library Repository Feedhttp://www.rssboard.org/rss-specificationpython-feedgenenMon, 11 Nov 2024 07:13:07 -0800Measured limits to contamination of optical surfaces by elastomers in vacuum
https://resolver.caltech.edu/CaltechAUTHORS:ABRao95
Year: 1995
We have monitored the reflectivity of mirrors that were exposed to a fluoroelastomer (3M-Fluorel 2176) and a room-temperature vulcanizing silicone rubber (RTV-615) in vacuum. The 95% confidence limit on the decrease of mirror reflectivities was less than 0.35 ppm/week for Fluorel and <0.29 ppm@week for RTV-615.https://resolver.caltech.edu/CaltechAUTHORS:ABRao95Improved sensitivity in a gravitational wave interferometer
and implications for LIGO
https://resolver.caltech.edu/CaltechAUTHORS:20140109-091703152
Year: 1996
DOI: 10.1016/0375-9601(96)00377-5
Sensitivity enhancements in the laser interferometer gravitational wave observatory (LIGO) project's 40 m interferometer have been achieved through two major instrumental improvements. Improved vibration isolation has reduced the noise due to ground motion. New test masses with less mechanical dissipation were installed to lower the thermal noise associated with mirror vibrations. The minimum interferometer noise (square root of the spectral density of apparent differential displacement) reached 3 x 10^(-19) m/Hz^(1/2) near 450 Hz.https://resolver.caltech.edu/CaltechAUTHORS:20140109-091703152Shot Noise in Gravitational-Wave Detectors with Fabry-Perot Arms
https://resolver.caltech.edu/CaltechAUTHORS:LYOao00
Year: 2000
Shot-noise-limited sensitivity is calculated for gravitational-wave interferometers with Fabry–Perot arms, similar to those being installed at the Laser Interferometer Gravitational-Wave Observatory (LIGO) and the Italian–French Laser Interferometer Collaboration (VIRGO) facility. This calculation includes the effect of nonstationary shot noise that is due to phase modulation of the light. The resulting formula is experimentally verified by a test interferometer with suspended mirrors in the 40-m arms.https://resolver.caltech.edu/CaltechAUTHORS:LYOao00Detector description and performance for the first coincidence
observations between LIGO and GEO
https://resolver.caltech.edu/CaltechAUTHORS:20140109-094808747
Year: 2004
DOI: 10.1016/j.nima.2003.11.124
For 17 days in August and September 2002, the LIGO and GEO interferometer gravitational wave detectors were operated in coincidence to produce their first data for scientific analysis. Although the detectors were still far from their design sensitivity levels, the data can be used to place better upper limits on the flux of gravitational waves incident on the earth than previous direct measurements. This paper describes the instruments and the data in some detail, as a companion to analysis papers based on the first data.https://resolver.caltech.edu/CaltechAUTHORS:20140109-094808747Upper limits on the strength of periodic gravitational waves from PSR J1939+2134
https://resolver.caltech.edu/CaltechAUTHORS:20140911-121323448
Year: 2004
DOI: 10.1088/0264-9381/21/5/042
The first science run of the LIGO and GEO gravitational wave detectors presented the opportunity to test methods of searching for gravitational waves from known pulsars. Here we present new direct upper limits on the strength of waves from the pulsar PSR J1939+2134 using two independent analysis methods, one in the frequency domain using frequentist statistics and one in the time domain using Bayesian inference. Both methods show that the strain amplitude at Earth from this pulsar is less than a few times 10^(-22).https://resolver.caltech.edu/CaltechAUTHORS:20140911-121323448Upper limits on the strength of periodic gravitational waves from PSR J1939+2134
https://resolver.caltech.edu/CaltechAUTHORS:20110708-115305907
Year: 2004
DOI: 10.1088/0264-9381/21/5/042
The first science run of the LIGO and GEO gravitational wave detectors presented the opportunity to test methods of searching for gravitational waves from known pulsars. Here we present new direct upper limits on the strength of waves from the pulsar PSR J1939+2134 using two independent analysis methods, one in the frequency domain using frequentist statistics and one in the time domain using Bayesian inference. Both methods show that the strain amplitude at Earth from this pulsar is less than a few times 10^(−22).https://resolver.caltech.edu/CaltechAUTHORS:20110708-115305907Setting upper limits on the strength of periodic gravitational waves from PSR J1939+2134 using the first science data from the GEO 600 and LIGO detectors
https://resolver.caltech.edu/CaltechAUTHORS:ABBprd04a
Year: 2004
DOI: 10.1103/PhysRevD.69.082004
Data collected by the GEO 600 and LIGO interferometric gravitational wave detectors during their first observational science run were searched for continuous gravitational waves from the pulsar J1939+2134 at twice its rotation frequency. Two independent analysis methods were used and are demonstrated in this paper: a frequency domain method and a time domain method. Both achieve consistent null results, placing new upper limits on the strength of the pulsar's gravitational wave emission. A model emission mechanism is used to interpret the limits as a constraint on the pulsar's equatorial ellipticity.https://resolver.caltech.edu/CaltechAUTHORS:ABBprd04aFirst upper limits from LIGO on gravitational wave bursts
https://resolver.caltech.edu/CaltechAUTHORS:ABBprd04b
Year: 2004
DOI: 10.1103/PhysRevD.69.082004
We report on a search for gravitational wave bursts using data from the first science run of the Laser Interferometer Gravitational Wave Observatory (LIGO) detectors. Our search focuses on bursts with durations ranging from 4 to 100 ms, and with significant power in the LIGO sensitivity band of 150 to 3000 Hz. We bound the rate for such detected bursts at less than 1.6 events per day at a 90% confidence level. This result is interpreted in terms of the detection efficiency for ad hoc waveforms (Gaussians and sine Gaussians) as a function of their root-sum-square strain h(rss); typical sensitivities lie in the range h(rss) ~10^(-19)-10^(-17) strain/√Hz, depending on the waveform. We discuss improvements in the search method that will be applied to future science data from LIGO and other gravitational wave detectors.https://resolver.caltech.edu/CaltechAUTHORS:ABBprd04bAnalysis of LIGO data for gravitational waves from binary neutron stars
https://resolver.caltech.edu/CaltechAUTHORS:ABBprd04d
Year: 2004
DOI: 10.1103/PhysRevD.69.122001
We report on a search for gravitational waves from coalescing compact binary systems in the Milky Way and the Magellanic Clouds. The analysis uses data taken by two of the three LIGO interferometers during the first LIGO science run and illustrates a method of setting upper limits on inspiral event rates using interferometer data. The analysis pipeline is described with particular attention to data selection and coincidence between the two interferometers. We establish an observational upper limit of R<1.7x10^(2) per year per Milky Way Equivalent Galaxy (MWEG), with 90% confidence, on the coalescence rate of binary systems in which each component has a mass in the range 1-3 M☉.https://resolver.caltech.edu/CaltechAUTHORS:ABBprd04dAnalysis of first LIGO science data for stochastic gravitational waves
https://resolver.caltech.edu/CaltechAUTHORS:ABBprd04c
Year: 2004
DOI: 10.1103/PhysRevD.69.122004
We present the analysis of between 50 and 100 h of coincident interferometric strain data used to search for and establish an upper limit on a stochastic background of gravitational radiation. These data come from the first LIGO science run, during which all three LIGO interferometers were operated over a 2-week period spanning August and September of 2002. The method of cross correlating the outputs of two interferometers is used for analysis. We describe in detail practical signal processing issues that arise when working with real data, and we establish an observational upper limit on a f^-3 power spectrum of gravitational waves. Our 90% confidence limit is Ω0h100(^2)<~23±4.6 in the frequency band 40–314 Hz, where h100 is the Hubble constant in units of 100 km/sec/Mpc and Ω0 is the gravitational wave energy density per logarithmic frequency interval in units of the closure density. This limit is approximately 104 times better than the previous, broadband direct limit using interferometric detectors, and nearly 3 times better than the best narrow-band bar detector limit. As LIGO and other worldwide detectors improve in sensitivity and attain their design goals, the analysis procedures described here should lead to stochastic background sensitivity levels of astrophysical interest.https://resolver.caltech.edu/CaltechAUTHORS:ABBprd04cLimits on Gravitational-Wave Emission from Selected Pulsars Using LIGO Data
https://resolver.caltech.edu/CaltechAUTHORS:20110503-112854281
Year: 2005
DOI: 10.1103/PhysRevLett.94.181103
We place direct upper limits on the amplitude of gravitational waves from 28 isolated radio pulsars by a coherent multidetector analysis of the data collected during the second science run of the LIGO interferometric detectors. These are the first direct upper limits for 26 of the 28 pulsars. We use coordinated radio observations for the first time to build radio-guided phase templates for the expected gravitational-wave signals. The unprecedented sensitivity of the detectors allows us to set strain upper limits as low as a few times 10^(-24). These strain limits translate into limits on the equatorial ellipticities of the pulsars, which are smaller than 10^(-5) for the four closest pulsars.https://resolver.caltech.edu/CaltechAUTHORS:20110503-112854281Search for gravitational waves associated with the gamma ray burst GRB030329 using the LIGO detectors
https://resolver.caltech.edu/CaltechAUTHORS:20140114-151827275
Year: 2005
DOI: 10.1103/PhysRevD.72.042002
We have performed a search for bursts of gravitational waves associated with the very bright gamma ray burst GRB030329, using the two detectors at the LIGO Hanford Observatory. Our search covered the most sensitive frequency range of the LIGO detectors (approximately 80–−2048 Hz), and we specifically targeted signals shorter than ≃150 ms. Our search algorithm looks for excess correlated power between the two interferometers and thus makes minimal assumptions about the gravitational waveform. We observed no candidates with gravitational-wave signal strength larger than a predetermined threshold. We report frequency-dependent upper limits on the strength of the gravitational waves associated with GRB030329. Near the most sensitive frequency region, around ≃250 Hz, our root-sum-square (RSS) gravitational-wave strain sensitivity for optimally polarized bursts was better than h_(RSS)≃6×10^(−21) Hz^(−1/2). Our result is comparable to the best published results searching for association between gravitational waves and gamma ray bursts.https://resolver.caltech.edu/CaltechAUTHORS:20140114-151827275Upper limits on gravitational wave bursts in LIGO's second science run
https://resolver.caltech.edu/CaltechAUTHORS:ABBprd05b
Year: 2005
DOI: 10.1103/PhysRevD.72.062001
We perform a search for gravitational wave bursts using data from the second science run of the LIGO detectors, using a method based on a wavelet time-frequency decomposition. This search is sensitive to bursts of duration much less than a second and with frequency content in the 100–1100 Hz range. It features significant improvements in the instrument sensitivity and in the analysis pipeline with respect to the burst search previously reported by LIGO. Improvements in the search method allow exploring weaker signals, relative to the detector noise floor, while maintaining a low false alarm rate, O(0.1) μHz. The sensitivity in terms of the root-sum-square (rss) strain amplitude lies in the range of hrss∼10^-20 - 10^-19 Hz^-1/2. No gravitational wave signals were detected in 9.98 days of analyzed data. We interpret the search result in terms of a frequentist upper limit on the rate of detectable gravitational wave bursts at the level of 0.26 events per day at 90% confidence level. We combine this limit with measurements of the detection efficiency for selected waveform morphologies in order to yield rate versus strength exclusion curves as well as to establish order-of-magnitude distance sensitivity to certain modeled astrophysical sources. Both the rate upper limit and its applicability to signal strengths improve our previously reported limits and reflect the most sensitive broad-band search for untriggered and unmodeled gravitational wave bursts to date.https://resolver.caltech.edu/CaltechAUTHORS:ABBprd05bSearch for gravitational waves from primordial black hole binary coalescences in the galactic halo
https://resolver.caltech.edu/CaltechAUTHORS:ABBprd05c
Year: 2005
DOI: 10.1103/PhysRevD.72.082002
We use data from the second science run of the LIGO gravitational-wave detectors to search for the gravitational waves from primordial black hole binary coalescence with component masses in the range 0.2–1.0M☉. The analysis requires a signal to be found in the data from both LIGO observatories, according to a set of coincidence criteria. No inspiral signals were found. Assuming a spherical halo with core radius 5 kpc extending to 50 kpc containing nonspinning black holes with masses in the range 0.2–1.0M☉, we place an observational upper limit on the rate of primordial black hole coalescence of 63 per year per Milky Way halo (MWH) with 90% confidence.https://resolver.caltech.edu/CaltechAUTHORS:ABBprd05cSearch for gravitational waves from galactic and extra-galactic binary neutron stars
https://resolver.caltech.edu/CaltechAUTHORS:ABBprd05d
Year: 2005
DOI: 10.1103/PhysRevD.72.082001
We use 373 hours (≈15 days) of data from the second science run of the LIGO gravitational-wave detectors to search for signals from binary neutron star coalescences within a maximum distance of about 1.5 Mpc, a volume of space which includes the Andromeda Galaxy and other galaxies of the Local Group of galaxies. This analysis requires a signal to be found in data from detectors at the two LIGO sites, according to a set of coincidence criteria. The background (accidental coincidence rate) is determined from the data and is used to judge the significance of event candidates. No inspiral gravitational-wave events were identified in our search. Using a population model which includes the Local Group, we establish an upper limit of less than 47 inspiral events per year per Milky Way equivalent galaxy with 90% confidence for nonspinning binary neutron star systems with component masses between 1 and 3M☉.https://resolver.caltech.edu/CaltechAUTHORS:ABBprd05dFirst all-sky upper limits from LIGO on the strength of periodic gravitational waves using the Hough transform
https://resolver.caltech.edu/CaltechAUTHORS:20110426-152707978
Year: 2005
DOI: 10.1103/PhysRevD.72.102004
We perform a wide parameter-space search for continuous gravitational waves over the whole sky and over a large range of values of the frequency and the first spin-down parameter. Our search method is based on the Hough transform, which is a semicoherent, computationally efficient, and robust pattern recognition technique. We apply this technique to data from the second science run of the LIGO detectors and our final results are all-sky upper limits on the strength of gravitational waves emitted by unknown isolated spinning neutron stars on a set of narrow frequency bands in the range 200–400 Hz. The best upper limit on the gravitational-wave strain amplitude that we obtain in this frequency range is 4.43×10^(-23).https://resolver.caltech.edu/CaltechAUTHORS:20110426-152707978Upper limits from the LIGO and TAMA detectors on the rate of gravitational-wave bursts
https://resolver.caltech.edu/CaltechAUTHORS:ABBprd05
Year: 2005
DOI: 10.1103/PhysRevD.72.122004
We report on the first joint search for gravitational waves by the TAMA and LIGO collaborations. We looked for millisecond-duration unmodeled gravitational-wave bursts in 473 hr of coincident data collected during early 2003. No candidate signals were found. We set an upper limit of 0.12 events per day on the rate of detectable gravitational-wave bursts, at 90% confidence level. From software simulations, we estimate that our detector network was sensitive to bursts with root-sum-square strain amplitude above approximately 1–3×10-19 Hz-1/2 in the frequency band 700-2000 Hz. We describe the details of this collaborative search, with particular emphasis on its advantages and disadvantages compared to searches by LIGO and TAMA separately using the same data. Benefits include a lower background and longer observation time, at some cost in sensitivity and bandwidth. We also demonstrate techniques for performing coincidence searches with a heterogeneous network of detectors with different noise spectra and orientations. These techniques include using coordinated software signal injections to estimate the network sensitivity, and tuning the analysis to maximize the sensitivity and the livetime, subject to constraints on the background.https://resolver.caltech.edu/CaltechAUTHORS:ABBprd05Search for gravitational waves from binary black hole inspirals in LIGO data
https://resolver.caltech.edu/CaltechAUTHORS:ABBprd06a
Year: 2006
DOI: 10.1103/PhysRevD.73.062001
We report on a search for gravitational waves from binary black hole inspirals in the data from the second science run of the LIGO interferometers. The search focused on binary systems with component masses between 3 and 20M_☉. Optimally oriented binaries with distances up to 1 Mpc could be detected with efficiency of at least 90%. We found no events that could be identified as gravitational waves in the 385.6 hours of data that we searched.https://resolver.caltech.edu/CaltechAUTHORS:ABBprd06aJoint LIGO and TAMA300 search for gravitational waves from inspiralling neutron star binaries
https://resolver.caltech.edu/CaltechAUTHORS:ABBprd06b
Year: 2006
DOI: 10.1103/PhysRevD.73.102002
We search for coincident gravitational wave signals from inspiralling neutron star binaries using LIGO and TAMA300 data taken during early 2003. Using a simple trigger exchange method, we perform an intercollaboration coincidence search during times when TAMA300 and only one of the LIGO sites were operational. We find no evidence of any gravitational wave signals. We place an observational upper limit on the rate of binary neutron star coalescence with component masses between 1 and 3Mסּ of 49 per year per Milky Way equivalent galaxy at a 90% confidence level. The methods developed during this search will find application in future network inspiral analyses.https://resolver.caltech.edu/CaltechAUTHORS:ABBprd06bCarbonate concretions as a window to the evolving chemistry of the early ocean and atmosphere
https://resolver.caltech.edu/CaltechAUTHORS:20140714-122718400
Year: 2007
DOI: 10.1016/j.gca.2007.06.020
Ellipsoidal calcium carbonate concretions with diameters ranging up to meter-scale are common in organic-rich shales throughout the Phanerozoic. These features arise through early (pre-compactional), highly localized cementation.https://resolver.caltech.edu/CaltechAUTHORS:20140714-122718400