Documentation for O4 Discovery Paper Data Release

This release includes data associated with notable events in O4 initially published outside of main catalogs. These may contain preliminary versions of data quality segments and calibration. When available, updated versions of these data products will be included in catalog paper releases.

GW230529_181500:

  • Publication: Gravitational Waves from the Coalescence of 1.4 Msun and 3.6 Msun Compact Objects. [ApJL] [DCC] [PDF] [arXiv]
  • LIGO Scientific Collaboration Announcement
  • GW230529: Observation of the merger of a neutron star and an unknown compact object Science Summary
  • Download Analysis Ready Data Products GW230529_181500
  • This version of the data release includes subtraction of noise contributions from non-linear couplings.†
  • At the time of GW230529_181500 only the L1 detector was observing.
  • Additional data products released in Zenodo
  • Each of the search pipelines provided an IFAR for both the online and the offline searches. These have been converted to FAR values (1/yr), with the far being the offline value for consistency with other events reported on GWOSC.
  • Only the DATA (Analysis Ready) Timeline and segment is provided for the L1 detector in this event. Other Timelines and segments will be included in the bulk data release. The full 4096 seconds of strain data are in analysis ready state.
  • Parameter estimation results were calculated using combined posterior samples from IMRPhenomXPHM and SEOBNRv5PHM waveform models.
  • The GWTC-4.0 catalog reanalyzed GW230529_181500 with several different waveform models. See the GWTC-4.0 entry for this event for details.

GW231123_135430:

  • Publication: GW231123: a Binary Black Hole Merger with Total Mass 190-265 M☉ [DCC]
  • LVK Press Release [PDF]
  • LVK Announcement for GW231123 discovery paper [Website]
  • GW231123 Science Summary. [PDF]
  • Download Analysis Ready Data Products GW231123_135430
  • Additional data products released in Zenodo
  • GW231123_135430 strain data is now aligned with the start and stop times found in full observing run data releases. Strain data begins at the GPS time 1384779776 (Thu Nov 23 13:02:38 UTC 2023) and spans 4096 seconds. The gravitation wave signal peaks at GPS time 1384782888.7, which is 3112.7 seconds into the downloadable files. Sample rates available are 16KHz and 4KHz sample rates. The format for strain is HDF and GWF file and provided for the H1 and L1 detectors.
  • Parameter estimation results were calculated using combined posterior samples from five models: NRSur7dq4, IMRPhenomTPHM, SEOBNRv5PHM, IMRPhenomXO4a, and IMRPhenomXPHM. The combined results, along with the results from each individual model, are presented as median values and 90% credible intervals. The posterior samples for models are available in Zenodo as a single compressed tar file.

Notes:

  • Small differences may exist between the values of parameter confidence intervals on the GWOSC website and those appearing in the papers for these events.
  • See Event Portal Usage Notes for additional notes.

† Sub60Hz cleaning method: Machine-learning nonstationary noise out of gravitational-wave detectors

Event Portal usage notes Event release technical details

Release Notes

  • GW230529_181500 added: Feb 29, 2024
  • Added additional information for GW230529_181500: Mar 14, 2024
  • Noted GW230529_181500 is an L1 detector event only: Mar 28, 2024
  • Public release of GW230529_181500: Apr 5, 2024
  • Added arXiv and Science Summary link for GW230529: Apr 8, 2024
  • Public release of GW231123_135430: July 14, 2025