This material is part of several data products associated with GWTC-2.1, an update to the second Gravitational-Wave Transient Catalog from the LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration. For more information, see the paper (https://dcc.ligo.org/LIGO-P2100063/public), the related material linked from this page, and the GWTC-2.1 data release documentation (https://www.gw-openscience.org/GWTC-2.1/). Parameter estimation data release This data release contains posterior samples (*.h5) for gravitational-wave candidates through the first part of the third observing run (O3a). We provide results for the 44 candidates that have a probability of astrophysical origin of over 0.5 from O3 as well as the 10 previously-reported binary-black-hole candidates from GWTC-1 (this excludes GW170817). There are two .h5 files per event Cosmologically reweighted (*cosmo.h5) Not cosmologically reweighted (*nocosmo.h5) The cosmologically reweighted posteriors are reweighted to have a luminosity-distance prior that has a uniform merger rate in the source's comoving frame. Each .h5 file contains samples for multiple runs with keys C01:RUN_NAME, where RUN_NAME is the waveform used for the run (and additional prior-choice information if necessary) or Mixed, indicating an equal mixture of samples from runs with similar physics if they exist. In cases where only one waveform was used, the Mixed dataset is simply a resampling of those results . GW190425 does not have Mixed samples. See the paper appendices for further information. In addition to containing the posterior samples, the .h5 files also contain metadata about the analyses including the configuration files (which specify details such as the detector data analyzed), noise power spectral densities (potentially for a superset of the detectors used in the analysis) and calibration uncertainty envelopes. The python notebook explains how to use the posterior samples. This data release also contains .FITS skymap files, which can be read with ligo.skymap, and skymap statistics in *.txt files. The inference of the source parameters were performed with Bilby, Parallel Bilby and RIFT. The results are formatted using PESummary. A similar release has been made to accompany GWTC-3 for results from the second part of the third observing run. How to download all files from this page If you would like to download all files on this page, we recommend zenodo_get: pip install zenodo_get zenodo-get RECORD_ID_OR_DOI where the record ID for the most recent version of this page is 5117702 and IDs for other versions can be found in the Versions section at the side of this page. For more general background on gravitational-wave parameter estimation, try the materials from a GW Open Data Workshop or the guide to LIGO–Virgo data analysis.

LIGO Laboratory and Advanced LIGO are funded by the United States National Science Foundation (NSF) as well as the Science and Technology Facilities Council (STFC) of the United Kingdom, the Max-Planck-Society (MPS), and the State of Niedersachsen/Germany for support of the construction of Advanced LIGO and construction and operation of the GEO600 detector. Additional support for Advanced LIGO was provided by the Australian Research Council. Virgo is funded, through the European Gravitational Observatory (EGO), by the French Centre National de Recherche Scientifique (CNRS), the Italian Istituto Nazionale di Fisica Nucleare (INFN) and the Dutch Nikhef, with contributions by institutions from Belgium, Germany, Greece, Hungary, Ireland, Japan, Monaco, Poland, Portugal, Spain.