Speaker
Description
The LIGO–Virgo–KAGRA (LVK) Collaboration closed its fourth observation period (O4) in November 2025, its longest and richest to date. During O4, the detectors observed roughly 250 gravitational-wave candidate signals in real time, and more are extracted from the data by offline analysis. Outstanding results were, for example, the first detection of “second generation” black holes, in which the primary objects are likely to be themselves the result of previous mergers, or the observation of the most massive black hole merger to date.
The LIGO, Virgo and KAGRA interferometers are now preparing for a new phase of technological upgrades and testing over the next few years, that will likely be implemented in stages interleaved by periods of science data taking: a new observation campaign is currently being planned to run for six months in 2026-27.
Over the years, the LVK computing model evolved to cope with higher event rates from more advanced detectors and a growing community of researchers, moving from custom-made tools running on a few dedicated clusters to distributed computing based on widely used technologies.
We provide an updated overview of the cyberinfrastructure that enabled O4 operations, spanning data management and distribution, low-latency analyses, alert management, offline data processing and support for Open Science activities. Also, operational experience from O4 is discussed, together with performance metrics and lessons learnt.
Finally, plans are presented for a further evolution of the infrastructure in view of continued growth in data volume, analysis complexity, and collaboration size.