108 research outputs found

    First joint observation by the underground gravitational-wave detector KAGRA with GEO 600

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    We report the results of the first joint observation of the KAGRA detector with GEO 600. KAGRA is a cryogenic and underground gravitational-wave detector consisting of a laser interferometer with 3 km arms, located in Kamioka, Gifu, Japan. GEO 600 is a British-German laser interferometer with 600 m arms, located near Hannover, Germany. GEO 600 and KAGRA performed a joint observing run from April 7 to 20, 2020. We present the results of the joint analysis of the GEO-KAGRA data for transient gravitational-wave signals, including the coalescence of neutron-star binaries and generic unmodeled transients. We also perform dedicated searches for binary coalescence signals and generic transients associated with gamma-ray burst events observed during the joint run. No gravitational-wave events were identified. We evaluate the minimum detectable amplitude for various types of transient signals and the spacetime volume for which the network is sensitive to binary neutron-star coalescences. We also place lower limits on the distances to the gamma-ray bursts analyzed based on the non-detection of an associated gravitational-wave signal for several signal models, including binary coalescences. These analyses demonstrate the feasibility and utility of KAGRA as a member of the global gravitational-wave detector network

    All-sky search for continuous gravitational waves from isolated neutron stars using Advanced LIGO and Advanced Virgo O3 data

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    We present results of an all-sky search for continuous gravitational waves which can be produced by spinning neutron stars with an asymmetry around their rotation axis, using data from the third observing run of the Advanced LIGO and Advanced Virgo detectors. Four different analysis methods are used to search in a gravitational-wave frequency band from 10 to 2048 Hz and a first frequency derivative from 108-10^{-8} to 10910^{-9} Hz/s. No statistically-significant periodic gravitational-wave signal is observed by any of the four searches. As a result, upper limits on the gravitational-wave strain amplitude h0h_0 are calculated. The best upper limits are obtained in the frequency range of 100 to 200 Hz and they are 1.1×1025{\sim}1.1\times10^{-25} at 95\% confidence-level. The minimum upper limit of 1.10×10251.10\times10^{-25} is achieved at a frequency 111.5 Hz. We also place constraints on the rates and abundances of nearby planetary- and asteroid-mass primordial black holes that could give rise to continuous gravitational-wave signals

    Search for continuous gravitational wave emission from the Milky Way center in O3 LIGO--Virgo data

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    We present a directed search for continuous gravitational wave (CW) signals emitted by spinning neutron stars located in the inner parsecs of the Galactic Center (GC). Compelling evidence for the presence of a numerous population of neutron stars has been reported in the literature, turning this region into a very interesting place to look for CWs. In this search, data from the full O3 LIGO--Virgo run in the detector frequency band [10,2000] Hz[10,2000]\rm~Hz have been used. No significant detection was found and 95%\% confidence level upper limits on the signal strain amplitude were computed, over the full search band, with the deepest limit of about 7.6×10267.6\times 10^{-26} at 142 Hz\simeq 142\rm~Hz. These results are significantly more constraining than those reported in previous searches. We use these limits to put constraints on the fiducial neutron star ellipticity and r-mode amplitude. These limits can be also translated into constraints in the black hole mass -- boson mass plane for a hypothetical population of boson clouds around spinning black holes located in the GC.Comment: 25 pages, 5 figure

    All-sky search for continuous gravitational waves from isolated neutron stars using Advanced LIGO and Advanced Virgo O3 data

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    We present results of an all-sky search for continuous gravitational waves which can be produced by spinning neutron stars with an asymmetry around their rotation axis, using data from the third observing run of the Advanced LIGO and Advanced Virgo detectors. Four different analysis methods are used to search in a gravitational-wave frequency band from 10 to 2048 Hz and a first frequency derivative from 108-10^{-8} to 10910^{-9} Hz/s. No statistically-significant periodic gravitational-wave signal is observed by any of the four searches. As a result, upper limits on the gravitational-wave strain amplitude h0h_0 are calculated. The best upper limits are obtained in the frequency range of 100 to 200 Hz and they are 1.1×1025{\sim}1.1\times10^{-25} at 95\% confidence-level. The minimum upper limit of 1.10×10251.10\times10^{-25} is achieved at a frequency 111.5 Hz. We also place constraints on the rates and abundances of nearby planetary- and asteroid-mass primordial black holes that could give rise to continuous gravitational-wave signals.Comment: 23 main text pages, 17 figure

    Search for gravitational waves from Scorpius X-1 with a hidden Markov model in O3 LIGO data

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    Constraints on the cosmic expansion history from GWTC-3

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    We use 47 gravitational-wave sources from the Third LIGO-Virgo-KAGRA Gravitational-Wave Transient Catalog (GWTC-3) to estimate the Hubble parameter H(z)H(z), including its current value, the Hubble constant H0H_0. Each gravitational-wave (GW) signal provides the luminosity distance to the source and we estimate the corresponding redshift using two methods: the redshifted masses and a galaxy catalog. Using the binary black hole (BBH) redshifted masses, we simultaneously infer the source mass distribution and H(z)H(z). The source mass distribution displays a peak around 34M34\, {\rm M_\odot}, followed by a drop-off. Assuming this mass scale does not evolve with redshift results in a H(z)H(z) measurement, yielding H0=687+12kms1Mpc1H_0=68^{+12}_{-7} {\rm km\,s^{-1}\,Mpc^{-1}} (68%68\% credible interval) when combined with the H0H_0 measurement from GW170817 and its electromagnetic counterpart. This represents an improvement of 17% with respect to the H0H_0 estimate from GWTC-1. The second method associates each GW event with its probable host galaxy in the catalog GLADE+, statistically marginalizing over the redshifts of each event's potential hosts. Assuming a fixed BBH population, we estimate a value of H0=686+8kms1Mpc1H_0=68^{+8}_{-6} {\rm km\,s^{-1}\,Mpc^{-1}} with the galaxy catalog method, an improvement of 42% with respect to our GWTC-1 result and 20% with respect to recent H0H_0 studies using GWTC-2 events. However, we show that this result is strongly impacted by assumptions about the BBH source mass distribution; the only event which is not strongly impacted by such assumptions (and is thus informative about H0H_0) is the well-localized event GW190814

    Search for gravitational waves from Scorpius X-1 with a hidden Markov model in O3 LIGO data

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    Results are presented for a semi-coherent search for continuous gravitational waves from the low-mass X-ray binary Scorpius X-1, using a hidden Markov model (HMM) to allow for spin wandering. This search improves on previous HMM-based searches of Laser Interferometer Gravitational-wave Observatory (LIGO) data by including the orbital period in the search template grid, and by analyzing data from the latest (third) observing run (O3). In the frequency range searched, from 60 to 500 Hz, we find no evidence of gravitational radiation. This is the most sensitive search for Scorpius X-1 using a HMM to date. For the most sensitive sub-band, starting at 256.06256.06Hz, we report an upper limit on gravitational wave strain (at 95%95 \% confidence) of h095%=6.16×1026h_{0}^{95\%}=6.16\times10^{-26}, assuming the orbital inclination angle takes its electromagnetically restricted value ι=44\iota=44^{\circ}. The upper limits on gravitational wave strain reported here are on average a factor of 3\sim 3 lower than in the O2 HMM search. This is the first Scorpius X-1 HMM search with upper limits that reach below the indirect torque-balance limit for certain sub-bands, assuming ι=44\iota=44^{\circ}

    Tests of General Relativity with GWTC-3

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    The ever-increasing number of detections of gravitational waves (GWs) from compact binaries by the Advanced LIGO and Advanced Virgo detectors allows us to perform ever-more sensitive tests of general relativity (GR) in the dynamical and strong-field regime of gravity. We perform a suite of tests of GR using the compact binary signals observed during the second half of the third observing run of those detectors. We restrict our analysis to the 15 confident signals that have false alarm rates 103yr1\leq 10^{-3}\, {\rm yr}^{-1}. In addition to signals consistent with binary black hole (BH) mergers, the new events include GW200115_042309, a signal consistent with a neutron star--BH merger. We find the residual power, after subtracting the best fit waveform from the data for each event, to be consistent with the detector noise. Additionally, we find all the post-Newtonian deformation coefficients to be consistent with the predictions from GR, with an improvement by a factor of ~2 in the -1PN parameter. We also find that the spin-induced quadrupole moments of the binary BH constituents are consistent with those of Kerr BHs in GR. We find no evidence for dispersion of GWs, non-GR modes of polarization, or post-merger echoes in the events that were analyzed. We update the bound on the mass of the graviton, at 90% credibility, to mg1.27×1023eV/c2m_g \leq 1.27 \times 10^{-23} \mathrm{eV}/c^2. The final mass and final spin as inferred from the pre-merger and post-merger parts of the waveform are consistent with each other. The studies of the properties of the remnant BHs, including deviations of the quasi-normal mode frequencies and damping times, show consistency with the predictions of GR. In addition to considering signals individually, we also combine results from the catalog of GW signals to calculate more precise population constraints. We find no evidence in support of physics beyond GR

    Search for gravitational-wave transients associated with magnetar bursts in Advanced LIGO and Advanced Virgo data from the third observing run

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    Gravitational waves are expected to be produced from neutron staroscillations associated with magnetar giant flares and short bursts. We presentthe results of a search for short-duration (milliseconds to seconds) andlong-duration (\sim 100 s) transient gravitational waves from 13 magnetarshort bursts observed during Advanced LIGO, Advanced Virgo and KAGRA's thirdobservation run. These 13 bursts come from two magnetars, SGR 1935++2154 andSwift J1818.0-1607. We also include three other electromagnetic burst eventsdetected by Fermi GBM which were identified as likely coming from one or moremagnetars, but they have no association with a known magnetar. No magnetargiant flares were detected during the analysis period. We find no evidence ofgravitational waves associated with any of these 16 bursts. We place upperbounds on the root-sum-square of the integrated gravitational-wave strain thatreach 2.2×10232.2 \times 10^{-23} /Hz/\sqrt{\text{Hz}} at 100 Hz for theshort-duration search and 8.7×10238.7 \times 10^{-23} /Hz/\sqrt{\text{Hz}} at 450450 Hzfor the long-duration search, given a detection efficiency of 50%. For aringdown signal at 1590 Hz targeted by the short-duration search the limit isset to 1.8×10221.8 \times 10^{-22} /Hz/\sqrt{\text{Hz}}. Using the estimated distanceto each magnetar, we derive upper bounds on the emitted gravitational-waveenergy of 3.2×10433.2 \times 10^{43} erg (7.3×10437.3 \times 10^{43} erg) for SGR1935++2154 and 8.2×10428.2 \times 10^{42} erg (2.8×10432.8 \times 10^{43} erg) for SwiftJ1818.0-1607, for the short-duration (long-duration) search. Assumingisotropic emission of electromagnetic radiation of the burst fluences, weconstrain the ratio of gravitational-wave energy to electromagnetic energy forbursts from SGR 1935++2154 with available fluence information. The lowest ofthese ratios is 3×1033 \times 10^3.<br

    Search for subsolar-mass binaries in the first half of Advanced LIGO’s and Advanced Virgo’s third observing run

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    We report on a search for compact binary coalescences where at least one binary component has a mass between 0.2 M_\odot and 1.0 M_\odot in Advanced LIGO and Advanced Virgo data collected between 1 April 2019 1500 UTC and 1 October 2019 1500 UTC. We extend previous analyses in two main ways: we include data from the Virgo detector and we allow for more unequal mass systems, with mass ratio q \geq 0.1. We do not report any gravitational-wave candidates. The most significant trigger has a false alarm rate of 0.14 \mathrm{yr}^-1. This implies an upper limit on the merger rate of subsolar binaries in the range [220–24200] \mathrm{Gpc}^{-3} \, \mathrm{yr}^{-1}, depending on the chirp mass of the binary. We use this upper limit to derive astrophysical constraints on two phenomenological models that could produce subsolar-mass compact objects. One is an isotropic distribution of equal-mass primordial black holes. Using this model, we find that the fraction of dark matter in primordial black holes is f_\mathrm{PBH}\equiv \Omega_\mathrm{PBH}/\Omega_\mathrm{DM}\lesssim 6\%. The other is a dissipative dark matter model, in which fermionic dark matter can collapse and form black holes. The upper limit on the fraction of dark matter black holes depends on the minimum mass of the black holes that can be formed: the most constraining result is obtained at M_\mathrm{min}=1 M_\odot, where f_\mathrm{DBH}\equiv \Omega_\mathrm{PBH}/\Omega_\mathrm{DM}\lesssim 0.003\%. These are the tightest limits on spinning subsolar-mass binaries to date
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