CaltechAUTHORS: Combined
https://feeds.library.caltech.edu/people/Raab-F-J/combined.rss
A Caltech Library Repository Feedhttp://www.rssboard.org/rss-specificationpython-feedgenenWed, 26 Jun 2024 13:18:29 -0700Recycling for a cleaner signal
https://resolver.caltech.edu/CaltechAUTHORS:20150512-103424071
Year: 1991
DOI: 10.1038/351098a0
Observation of gravitational waves, the ripples
in spacetime emitted by violent cosmic
events such as the deaths of stars and the
births of black holes, could revolutionize
our understanding of astrophysics. Several
groups are engaged in attempts to build
gravitational-wave observatories based on
advanced laser interferometers. Efforts at
this frontier have spawned new techniques,
such as light recycling and the use of
squeezed light to maximize the detectors'
sensitivity. A new tool, called dual recycling,
has been demonstrated which allows more
efficient use of laser light and provides an
elegant method of tailoring the bandwidths
of these detectors.https://resolver.caltech.edu/CaltechAUTHORS:20150512-103424071LIGO: The Laser Interferometer Gravitational-Wave Observatory
https://resolver.caltech.edu/CaltechAUTHORS:20140110-115839088
Year: 1992
DOI: 10.1126/science.256.5055.325
The goal of the Laser Interferometer Gravitational-Wave Observatory (LIGO) Project is to detect and study astrophysical gravitational waves and use data from them for research in physics and astronomy. LIGO will support studies concerning the nature and nonlinear dynamics of gravity, the structures of black holes, and the equation of state of nuclear matter. It will also measure the masses, birth rates, collisions, and distributions of black holes and neutron stars in the universe and probe the cores of supernovae and the very early universe. The technology for LIGO has been developed during the past 20 years. Construction will begin in 1992, and under the present schedule, LIGO's gravitational-wave searches will begin in 1998.https://resolver.caltech.edu/CaltechAUTHORS:20140110-115839088Measured 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:ABRao95Demonstration of a power-recycled Michelson interferometer with Fabry-Perot arms by frontal modulation
https://resolver.caltech.edu/CaltechAUTHORS:REGol95
Year: 1995
Large-scale gravitational-wave detectors currently under construction such as the LIGO detectors use multiple-mirror resonant optical systems containing several surfaces at which the relative phase of interfering light beams must be controlled. We describe a tabletop experiment that demonstrates a scheme for extracting signals in such an interferometer corresponding to deviations from perfect interference.https://resolver.caltech.edu/CaltechAUTHORS:REGol95Improved 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:LYOao00Search for gravitational-wave bursts in LIGO's third science run
https://resolver.caltech.edu/CaltechAUTHORS:ABBcqg06
Year: 2006
DOI: 10.1088/0264-9381/23/8/S05
We report on a search for gravitational-wave bursts in data from the three LIGO interferometric detectors during their third science run. The search targets subsecond bursts in the frequency range 100-1100 Hz for which no waveform model is assumed and has a sensitivity in terms of the root-sum-square (rss) strain amplitude of h(rss) ~10^(-20) Hz^(-1/2). No gravitational-wave signals were detected in the eight days of analysed data.https://resolver.caltech.edu/CaltechAUTHORS:ABBcqg06A joint search for gravitational wave bursts with AURIGA and LIGO
https://resolver.caltech.edu/CaltechAUTHORS:20090630-134133512
Year: 2008
DOI: 10.1088/0264-9381/25/9/095004
The first simultaneous operation of the AURIGA detector and the LIGO observatory was an opportunity to explore real data, joint analysis methods between two very different types of gravitational wave detectors: resonant bars and interferometers. This paper describes a coincident gravitational wave burst search, where data from the LIGO interferometers are cross-correlated at the time of AURIGA candidate events to identify coincident transients. The analysis pipeline is tuned with two thresholds, on the signal-to-noise ratio of AURIGA candidate events and on the significance of the cross-correlation test in LIGO. The false alarm rate is estimated by introducing time shifts between data sets and the network detection efficiency is measured by adding simulated gravitational wave signals to the detector output. The simulated waveforms have a significant fraction of power in the narrower AURIGA band. In the absence of a detection, we discuss how to set an upper limit on the rate of gravitational waves and to interpret it according to different source models. Due to the short amount of analyzed data and to the high rate of non-Gaussian transients in the detectors' noise at the time, the relevance of this study is methodological: this was the first joint search for gravitational wave bursts among detectors with such different spectral sensitivity and the first opportunity for the resonant and interferometric communities to unify languages and techniques in the pursuit of their common goal.https://resolver.caltech.edu/CaltechAUTHORS:20090630-134133512The LSC glitch group: monitoring noise transients during the fifth LIGO science run
https://resolver.caltech.edu/CaltechAUTHORS:BLAcqg08
Year: 2008
DOI: 10.1088/0264-9381/25/18/184004
The LIGO Scientific Collaboration (LSC) glitch group is part of the LIGO detector characterization effort. It consists of data analysts and detector experts who, during and after science runs, collaborate for a better understanding of noise transients in the detectors. Goals of the glitch group during the fifth LIGO science run (S5) included (1) offline assessment of the detector data quality, with focus on noise transients, (2) veto recommendations for astrophysical analysis and (3) feedback to the commissioning team on anomalies seen in gravitational wave and auxiliary data channels. Other activities included the study of auto-correlation of triggers from burst searches, stationarity of the detector noise and veto studies. The group identified causes for several noise transients that triggered false alarms in the gravitational wave searches; the times of such transients were identified and vetoed from the data generating the LSC astrophysical results.https://resolver.caltech.edu/CaltechAUTHORS:BLAcqg08All-Sky LIGO Search for Periodic Gravitational Waves in the Early Fifth-Science-Run Data
https://resolver.caltech.edu/CaltechAUTHORS:20090622-105124641
Year: 2009
DOI: 10.1103/PhysRevLett.102.111102
We report on an all-sky search with the LIGO detectors for periodic gravitational waves in the frequency range 50–1100 Hz and with the frequency's time derivative in the range -5 x 10^(-9)–0 Hzs^(-1). Data from the first eight months of the fifth LIGO science run (S5) have been used in this search, which is based on a semicoherent method (PowerFlux) of summing strain power. Observing no evidence of periodic gravitational radiation, we report 95% confidence-level upper limits on radiation emitted by any unknown isolated rotating neutron stars within the search range. Strain limits below 10^(-24) are obtained over a 200-Hz band, and the sensitivity improvement over previous searches increases the spatial volume sampled by an average factor of about 100 over the entire search band. For a neutron star with nominal equatorial ellipticity of 10^-6, the search is sensitive to distances as great as 500 pc.https://resolver.caltech.edu/CaltechAUTHORS:20090622-105124641Search for gravitational waves from low mass binary coalescences in the first year of LIGO's S5 data
https://resolver.caltech.edu/CaltechAUTHORS:20091007-073406265
Year: 2009
DOI: 10.1103/PhysRevD.79.122001
We have searched for gravitational waves from coalescing low mass compact binary systems with a total mass between 2M_([sun]) and 35Mz-([sun]) and a minimum component mass of 1M_([sun]) using data from the first year of the fifth science run of the three LIGO detectors, operating at design sensitivity. Depending on the mass, we are sensitive to coalescences as far as 150 Mpc from the Earth. No gravitational-wave signals were observed above the expected background. Assuming a population of compact binary objects with a Gaussian mass distribution representing binary neutron star systems, black hole–neutron star binary systems, and binary black hole systems, we calculate the 90% confidence upper limit on the rate of coalescences to be 3.9×10^(-2) yr^(-1)L_(10)^(-1), 1.1×10^(-2) yr^(-1)L_(10)^(-1), and 2.5×10^(-3)yr^(-1)L_(10)^(-1), respectively, where L_(10) is 10^(10) times the blue solar luminosity. We also set improved upper limits on the rate of compact binary coalescences per unit blue-light luminosity, as a function of mass.https://resolver.caltech.edu/CaltechAUTHORS:20091007-073406265LIGO: the Laser Interferometer Gravitational-Wave Observatory
https://resolver.caltech.edu/CaltechAUTHORS:20090925-102147548
Year: 2009
DOI: 10.1088/0034-4885/72/7/076901
The goal of the Laser Interferometric Gravitational-Wave Observatory (LIGO) is to detect and study gravitational waves (GWs) of astrophysical origin. Direct detection of GWs holds the promise of testing general relativity in the strong-field regime, of providing a new probe of exotic objects such as black holes and neutron stars and of uncovering unanticipated new astrophysics. LIGO, a joint Caltech–MIT project supported by the National Science Foundation, operates three multi-kilometer interferometers at two widely separated sites in the United States. These detectors are the result of decades of worldwide technology development, design, construction and commissioning. They are now operating at their design sensitivity, and are sensitive to gravitational wave strains smaller than one part in 10^(21). With this unprecedented sensitivity, the data are being analyzed to detect or place limits on GWs from a variety of potential astrophysical sources.https://resolver.caltech.edu/CaltechAUTHORS:20090925-102147548Einstein@Home search for periodic gravitational waves in early S5 LIGO data
https://resolver.caltech.edu/CaltechAUTHORS:20091020-142129445
Year: 2009
DOI: 10.1103/PhysRevD.80.042003
This paper reports on an all-sky search for periodic gravitational waves from sources such as deformed
isolated rapidly spinning neutron stars. The analysis uses 840 hours of data from 66 days of the fifth LIGO
science run (S5). The data were searched for quasimonochromatic waves with frequencies f in the range
from 50 to 1500 Hz, with a linear frequency drift _ƒ (measured at the solar system barycenter) in the range
-ƒ/T < ƒ_ < 0:1ƒ/T, for a minimum spin-down age T of 1000 years for signals below 400 Hz and
8000 years above 400 Hz. The main computational work of the search was distributed over approximately
100 000 computers volunteered by the general public. This large computing power allowed the use of a
relatively long coherent integration time of 30 hours while searching a large parameter space. This search
extends Einstein@Home's previous search in LIGO S4 data to about 3 times better sensitivity. No
statistically significant signals were found. In the 125–225 Hz band, more than 90% of sources with
dimensionless gravitational-wave strain tensor amplitude greater than 3 X 10^(-24) would have been
detected.https://resolver.caltech.edu/CaltechAUTHORS:20091020-142129445Search for gravitational waves from low mass compact binary coalescence in 186 days of LIGO's fifth science run
https://resolver.caltech.edu/CaltechAUTHORS:20091007-094829151
Year: 2009
DOI: 10.1103/PhysRevD.80.047101
We report on a search for gravitational waves from coalescing compact binaries, of total mass between 2 and 35M_☉, using LIGO observations between November 14, 2006 and May 18, 2007. No gravitational-wave signals were detected. We report upper limits on the rate of compact binary coalescence as a function of total mass. The LIGO cumulative 90%-confidence rate upper limits of the binary coalescence of neutron stars, black holes and black hole-neutron star systems are 1.4 × 10^(-2), 7.3 × 10(-4) and 3.6 × 10(-3) yr(-1) L_10^(-1), respectively, where L_(10_ is 10^(10) times the blue solar luminosityhttps://resolver.caltech.edu/CaltechAUTHORS:20091007-094829151Stacked Search for Gravitational Waves from the 2006 SGR 1900+14 Storm
https://resolver.caltech.edu/CaltechAUTHORS:20090901-112329874
Year: 2009
DOI: 10.1088/0004-637X/701/2/L68
We present the results of a LIGO search for short-duration gravitational waves (GWs) associated with the 2006 March 29 SGR 1900+14 storm. A new search method is used, "stacking" the GW data around the times of individual soft-gamma bursts in the storm to enhance sensitivity for models in which multiple bursts are accompanied by GW emission. We assume that variation in the time difference between burst electromagnetic emission and potential burst GW emission is small relative to the GW signal duration, and we time-align GW excess power time-frequency tilings containing individual burst triggers to their corresponding electromagnetic emissions. We use two GW emission models in our search: a fluence-weighted model and a flat (unweighted) model for the most electromagnetically energetic bursts. We find no evidence of GWs associated with either model. Model-dependent GW strain, isotropic GW emission energy E_(GW), and γ ≡ E_(GW)/E_(EM) upper limits are estimated using a variety of assumed waveforms. The stacking method allows us to set the most stringent model-dependent limits on transient GW strain published to date. We find E_(GW) upper limit estimates (at a nominal distance of 10 kpc) of between 2 × 10^(45) erg and 6 × 10^(50) erg depending on the waveform type. These limits are an order of magnitude lower than upper limits published previously for this storm and overlap with the range of electromagnetic energies emitted in soft gamma repeater (SGR) giant flares.https://resolver.caltech.edu/CaltechAUTHORS:20090901-112329874Search for gravitational wave ringdowns from perturbed black holes in LIGO S4 data
https://resolver.caltech.edu/CaltechAUTHORS:20091023-111958820
Year: 2009
DOI: 10.1103/PhysRevD.80.062001
According to general relativity a perturbed black hole will settle to a stationary configuration by the
emission of gravitational radiation. Such a perturbation will occur, for example, in the coalescence of a
black hole binary, following their inspiral and subsequent merger. At late times the waveform is a
superposition of quasinormal modes, which we refer to as the ringdown. The dominant mode is expected
to be the fundamental mode, l = m = 2. Since this is a well-known waveform, matched filtering can be
implemented to search for this signal using LIGO data. We present a search for gravitational waves from
black hole ringdowns in the fourth LIGO science run S4, during which LIGO was sensitive to the
dominant mode of perturbed black holes with masses in the range of 10M_☉ to 500M_☉, the regime of
intermediate-mass black holes, to distances up to 300 Mpc. We present a search for gravitational waves
from black hole ringdowns using data from S4. No gravitational wave candidates were found; we place a
90%-confidence upper limit on the rate of ringdowns from black holes with mass between 85M_☉ and
390M_☉ in the local universe, assuming a uniform distribution of sources, of 3:2 X 10^(-5) yr^(-1) Mpc^(-3)=
1:6 X 10^(-3) yr^(-1)L_10-^1 L_(10) ; where L_(10) is 10^(10) times the solar blue-light luminosity.https://resolver.caltech.edu/CaltechAUTHORS:20091023-111958820First LIGO search for gravitational wave bursts from cosmic (super)strings
https://resolver.caltech.edu/CaltechAUTHORS:20091021-153057198
Year: 2009
DOI: 10.1103/PhysRevD.80.062002
We report on a matched-filter search for gravitational wave bursts from cosmic string cusps using LIGO data from the fourth science run (S4) which took place in February and March 2005. No gravitational waves were detected in 14.9 days of data from times when all three LIGO detectors were operating. We interpret the result in terms of a frequentist upper limit on the rate of gravitational wave bursts and use the limits on the rate to constrain the parameter space (string tension, reconnection probability, and loop sizes) of cosmic string models. Many grand unified theory-scale models (with string tension Gµ/c^2[approximate]10^(-6)) can be ruled out at 90% confidence for reconnection probabilities p<=10^(-3) if loop sizes are set by gravitational back reaction.https://resolver.caltech.edu/CaltechAUTHORS:20091021-153057198Search for high frequency gravitational-wave bursts in the first calendar year of LIGO's fifth science run
https://resolver.caltech.edu/CaltechAUTHORS:20100419-091739093
Year: 2009
DOI: 10.1103/PhysRevD.80.102002
We present an all-sky search for gravitational waves in the frequency range 1 to 6 kHz during the first calendar year of LIGO's fifth science run. This is the first untriggered LIGO burst analysis to be conducted above 3 kHz. We discuss the unique properties of interferometric data in this regime. 161.3 days of triple-coincident data were analyzed. No gravitational events above threshold were observed and a frequentist upper limit of 5.4 year^(-1) on the rate of strong gravitational-wave bursts was placed at a 90% confidence level. Implications for specific theoretical models of gravitational-wave emission are also discussed.https://resolver.caltech.edu/CaltechAUTHORS:20100419-091739093The first direct detection of gravitational waves opens a vast new frontier in astronomy
https://resolver.caltech.edu/CaltechAUTHORS:20170911-130550468
Year: 2017
The first direct detection of gravitational waves (GWs),
announced on 11 February 2016, has opened a vast new
frontier in astronomy. Albert Einstein predicted the existence of these waves about a century ago as a consequence of his general theory of relativity. Radio
astronomy observations of the binary pulsar system PSR
1913 + 16 over a 20 year period beginning in 1975 provided
strong observational evidence that gravitational waves carried energy away from the orbits of neutron stars at precisely the level predicted by general relativity
(GR). This relentless conversion of orbital energy into
gravitational wave energy causes binary orbits to decay
until the objects eventually collide and merge. The frontier
of precision measurement science, using laser interferometers, was pushed for more than four decades to
achieve this first direct detection, marking a milestone in
experimental physics and engineering. Even more significantly, this milestone also opens a new window onto our universe and a completely new kind of astronomy to
explore.https://resolver.caltech.edu/CaltechAUTHORS:20170911-130550468Sensitivity to Gravitational Waves from Compact Binary Coalescences Achieved during LIGO's Fifth and Virgo's First Science Run
https://resolver.caltech.edu/CaltechAUTHORS:20230926-170843564
Year: 2023
DOI: 10.48550/arXiv.1003.2481
We summarize the sensitivity achieved by the LIGO and Virgo gravitational wave detectors for compact binary coalescence (CBC) searches during LIGO's fifth science run and Virgo's first science run. We present noise spectral density curves for each of the four detectors that operated during these science runs which are representative of the typical performance achieved by the detectors for CBC searches. These spectra are intended for release to the public as a summary of detector performance for CBC searches during these science runs.https://resolver.caltech.edu/CaltechAUTHORS:20230926-170843564