The Gravitational Wave Open Science Center (GWOSC), operated on behalf of the LIGO Scientific Collaboration, the Virgo Collaboration, and KAGRA (together, the LVK Collaboration), is the public data repository through which anyone can download strain data, event catalogs, and analysis tools from the LIGO, Virgo, and KAGRA gravitational-wave detectors. It is hosted at gwosc.org. This page covers GWOSC as a research data repository: what it holds, how releases are organized, the tools researchers use to work with the data, and how it fits into the wider research-data-management picture. It does not cover how LVK papers assign author order or credit on discovery papers with hundreds of named collaborators — for that, see CASRAI’s guide to authorship in high-energy-physics megacollaborations, including LIGO.
What GWOSC is
GWOSC is a domain repository (also called a discipline-specific repository): a data repository built around one research domain’s specific data types, formats, and analysis conventions, rather than a generalist repository that accepts any file type from any field. Its core holdings are strain time-series data — the calibrated record of the tiny, sub-fraction-of-a-proton-diameter distortions in detector arm length that constitute the raw measurement of a passing gravitational wave — alongside the processed event catalogs, software libraries, and tutorials needed to work with that data. GWOSC serves three detector networks: the two LIGO observatories (Hanford, designated H1, and Livingston, designated L1) in the United States, the Virgo detector (V1) in Italy, and KAGRA (K1) in Japan; which detectors contributed strain data to a given observing run varies by run, since not every detector has operated, or been included in every public release, at every point in the network’s history.
How the data is organized: observing runs and strain releases
GWOSC data is organized by observing run, each covering a defined date range and a defined set of contributing detectors. Published observing-run segments include O1 (September 2015 – January 2016, H1/L1), O2 (November 2016 – August 2017, H1/L1/V1), O3a (April – October 2019, H1/L1/V1), O3b (November 2019 – March 2020, H1/L1/V1), O4a (May 2023 – January 2024, H1/L1), and O4b (April 2024 – January 2025, H1/L1/V1). For each run, GWOSC publishes strain time-series data at two sample rates — a 4096 Hz (‘4 kHz’) set and a 16384 Hz (’16 kHz’) set — alongside data-quality and auxiliary-channel information researchers use to identify periods contaminated by instrumental or environmental noise. All GWOSC data is released under a Creative Commons Attribution 4.0 (CC BY 4.0) license, with acknowledgement text GWOSC asks users to include in any resulting publication.
The O4b release and the current gravitational-wave catalog
The most recent full observing-run release as of this writing is O4b, the second segment of the LVK network’s fourth observing run, covering April 2024 through January 2025 with strain data from the H1, L1, and V1 detectors (Virgo rejoined the network partway through O4, so O4a strain data covers only the two LIGO detectors). Alongside the O4b strain release, the LVK Collaboration published GWTC-5.0, the fifth version of the cumulative Gravitational-Wave Transient Catalog, which lists confident detections identified through the end of O4b together with updated results for events from earlier runs. GWTC-5.0 follows GWTC-4.0 (which added O4a-period detections to the catalog) in a versioning pattern that has run since the original GWTC-1 catalog covering the O1–O2 era detections, including the first confirmed detection, GW150914. Each catalog version is accompanied by a discovery paper on arXiv and by per-event parameter-estimation data products released through GWOSC’s event portal, alongside supplementary datasets tied to specific runs, such as strain data around notable transients identified by other observatories during the same period.
How researchers use GWOSC
GWOSC is built for reuse by people outside the LVK Collaboration itself — a defining feature of a well-run open-science repository, and part of why it is a useful reference case for research-data-management practice generally. Its main access points are:
- Bulk strain data download, organized by observing run and detector, in standard gravitational-wave-astronomy file formats, for researchers running their own search or parameter-estimation pipelines.
- The event catalog (GWTC), browsable and queryable through GWOSC’s event portal, giving access to confirmed-detection parameters (masses, distance, sky localization, and related quantities) without requiring a user to reprocess raw strain data themselves.
- Software tools and tutorials, including worked examples for common Python gravitational-wave-analysis packages, aimed at users who are not LVK members and may be approaching the data for the first time — a teaching function GWOSC has run through recurring Open Data Workshops.
- Utility web applications, such as a GPS-time converter (gravitational-wave timestamps are recorded in GPS time, not calendar time, which trips up new users) and a source-visibility checker for a given sky position and detector network.
This combination — raw data, a curated derived-product catalog, software, and onboarding material, all under one open license and one citation convention — is close to the practical definition of what a domain repository is supposed to provide, and is a useful concrete example when explaining that concept to researchers or administrators outside physics.
Why this matters for research administration
GWOSC is relevant to CASRAI’s audience beyond astrophysics for two reasons. First, it is a working, mature example of the domain-repository model that funder data management plan requirements increasingly ask researchers to name and justify: it is field-appropriate, it has a clear license and citation requirement, and its long-term availability is backed by a large international collaboration rather than a single grant. Administrators reviewing a DMP that proposes depositing data with a domain repository can use GWOSC’s structure — defined release cadence, explicit license, documented acknowledgement text, machine-accessible catalogs — as a reference point for what a credible repository commitment looks like, alongside registries such as re3data that catalog repositories against this kind of criteria. Second, GWOSC illustrates a distinction research offices increasingly need to draw for large collaborations: the data repository and its licensing terms are a separate governance question from authorship and credit on papers analyzing that data. A researcher can download and reanalyze public GWOSC strain data without being an LVK Collaboration member or author on an LVK discovery paper; how the original discovery paper itself assigns author order among its hundreds of named contributors is a different question, covered in CASRAI’s guide to megacollaboration authorship in ATLAS, CMS, and LIGO, and in the related guide to astronomy survey authorship conventions.
Frequently asked questions
Is GWOSC data free to use, including for commercial or non-academic purposes?
Yes. GWOSC releases its data under a CC BY 4.0 license, which permits reuse, including commercial reuse, provided the required attribution is given. GWOSC publishes specific acknowledgement text for this purpose.
Does GWOSC include KAGRA data?
GWOSC serves data from the full LVK network, and KAGRA (K1) is a full member of that collaboration, but not every observing-run release to date has included KAGRA strain data as part of the public data release for that specific run — contributing detectors vary by run, largely because of each detector’s operating schedule and sensitivity commissioning status at the time. Check the specific observing-run page on gwosc.org for which detectors are included in a given release.
What is the difference between GWTC and a GWOSC strain data release?
A strain data release is the underlying time-series measurement from the detectors for a given observing run. The Gravitational-Wave Transient Catalog (GWTC) is a separate, curated product: the list of confirmed detections found in that data, together with their estimated physical parameters. Researchers doing their own search pipeline development typically need the strain data; researchers doing population studies or follow-up on known events typically work from the GWTC catalog.
Do I need to be a LIGO, Virgo, or KAGRA collaboration member to use GWOSC data?
No. GWOSC exists specifically to make this data usable by researchers, students, and developers outside the LVK Collaboration, without requiring membership, a data use agreement, or restricted-access approval.
