5 research outputs found
BILBY : A User-friendly Bayesian Inference Library for Gravitational-wave Astronomy
No full textBayesian parameter estimation is fast becoming the language of gravitational-wave astronomy. It is the method by which gravitational-wave data is used to infer the sources' astrophysical properties. We introduce a user-friendly Bayesian inference library for gravitational-wave astronomy, Bilby. This Python code provides expert-level parameter estimation infrastructure with straightforward syntax and tools that facilitate use by beginners. It allows users to perform accurate and reliable gravitational-wave parameter estimation on both real, freely available data from LIGO/Virgo and simulated data. We provide a suite of examples for the analysis of compact binary mergers and other types of signal models, including supernovae and the remnants of binary neutron star mergers. These examples illustrate how to change the signal model, implement new likelihood functions, and add new detectors. Bilby has additional functionality to do population studies using hierarchical Bayesian modeling. We provide an example in which we infer the shape of the black hole mass distribution from an ensemble of observations of binary black hole mergers
Bilby: A User-friendly Bayesian Inference Library for Gravitational-wave Astronomy
No full textBayesian parameter estimation is fast becoming the language of gravitational-wave astronomy. It is the method by which gravitational-wave data is used to infer the sources' astrophysical properties. We introduce a user-friendly Bayesian inference library for gravitational-wave astronomy, BILBY. This PYTHON code provides expert-level parameter estimation infrastructure with straightforward syntax and tools that facilitate use by beginners. It allows users to perform accurate and reliable gravitational-wave parameter estimation on both real, freely available data from LIGO/Virgo and simulated data. We provide a suite of examples for the analysis of compact binary mergers and other types of signal models, including supernovae and the remnants of binary neutron star mergers. These examples illustrate how to change the signal model, implement new likelihood functions, and add new detectors. BILBY has additional functionality to do population studies using hierarchical Bayesian modeling. We provide an example in which we infer the shape of the black hole mass distribution from an ensemble of observations of binary black hole mergers.</p
Search for intermediate-mass black hole binaries in the third observing run of Advanced LIGO and Advanced Virgo
No full textInternational audienceIntermediate-mass black holes (IMBHs) span the approximate mass range 100−105 M⊙, between black holes (BHs) that formed by stellar collapse and the supermassive BHs at the centers of galaxies. Mergers of IMBH binaries are the most energetic gravitational-wave sources accessible by the terrestrial detector network. Searches of the first two observing runs of Advanced LIGO and Advanced Virgo did not yield any significant IMBH binary signals. In the third observing run (O3), the increased network sensitivity enabled the detection of GW190521, a signal consistent with a binary merger of mass ∼150 M⊙ providing direct evidence of IMBH formation. Here, we report on a dedicated search of O3 data for further IMBH binary mergers, combining both modeled (matched filter) and model-independent search methods. We find some marginal candidates, but none are sufficiently significant to indicate detection of further IMBH mergers. We quantify the sensitivity of the individual search methods and of the combined search using a suite of IMBH binary signals obtained via numerical relativity, including the effects of spins misaligned with the binary orbital axis, and present the resulting upper limits on astrophysical merger rates. Our most stringent limit is for equal mass and aligned spin BH binary of total mass 200 M⊙ and effective aligned spin 0.8 at 0.056 Gpc−3 yr−1 (90% confidence), a factor of 3.5 more constraining than previous LIGO-Virgo limits. We also update the estimated rate of mergers similar to GW190521 to 0.08 Gpc−3 yr−1.Key words: gravitational waves / stars: black holes / black hole physicsCorresponding author: W. Del Pozzo, e-mail: [email protected]† Deceased, August 2020
GWTC-3: Compact Binary Coalescences Observed by LIGO and Virgo During the Second Part of the Third Observing Run
No full textThe third Gravitational-Wave Transient Catalog (GWTC-3) describes signals
detected with Advanced LIGO and Advanced Virgo up to the end of their third
observing run. Updating the previous GWTC-2.1, we present candidate
gravitational waves from compact binary coalescences during the second half of
the third observing run (O3b) between 1 November 2019, 15:00 UTC and 27 March
2020, 17:00 UTC. There are 35 compact binary coalescence candidates identified
by at least one of our search algorithms with a probability of astrophysical
origin . Of these, 18 were previously reported as
low-latency public alerts, and 17 are reported here for the first time. Based
upon estimates for the component masses, our O3b candidates with
are consistent with gravitational-wave signals from
binary black holes or neutron star-black hole binaries, and we identify none
from binary neutron stars. However, from the gravitational-wave data alone, we
are not able to measure matter effects that distinguish whether the binary
components are neutron stars or black holes. The range of inferred component
masses is similar to that found with previous catalogs, but the O3b candidates
include the first confident observations of neutron star-black hole binaries.
Including the 35 candidates from O3b in addition to those from GWTC-2.1, GWTC-3
contains 90 candidates found by our analysis with
across the first three observing runs. These observations of compact binary
coalescences present an unprecedented view of the properties of black holes and
neutron stars.Comment: 88 pages (10 pages author list, 31 pages main text, 1 page
acknowledgements, 24 pages appendices, 22 pages bibliography), 17 figures, 16
tables. Update to match version to be published in Physical Review X. Data
products available from https://gwosc.org/GWTC-3
Open data from the first and second observing runs of Advanced LIGO and Advanced Virgo
No full textAdvanced LIGO and Advanced Virgo are actively monitoring the sky and collecting gravitational-wave strain data with sufficient sensitivity to detect signals routinely. In this paper we describe the data recorded by these instruments during their first and second observing runs. The main data products are the gravitational-wave strain arrays, released as time series sampled at 16384 Hz. The datasets that include this strain measurement can be freely accessed through the Gravitational Wave Open Science Center at http://gw-openscience.org, together with data-quality information essential for the analysis of LIGO and Virgo data, documentation, tutorials, and supporting software
