LIGO, VIRGO AND KAGRA OBSERVING RUN PLANS

(15 December 2024 update; next update 15 January 2024 or sooner)

The LIGO Livingston detector has been observing with a BNS range of 160-165 Mpc, and a duty cycle of 70-80%. LIGO Hanford has been observing at around 160 Mpc, and a duty cycle of around 50%. The Hanford duty cycle has been impacted this last month by a faulty laser that was recently fixed.

Virgo continues observing in O4b, with a duty cycle around 70% and a 50-55 Mpc BNS range. Currently, the Virgo Collaboration is reassessing its plans for O5 and both the entry date into O5 and the target sensitivity are unclear. This work is progressing and we expect to be able to define our plans for O5 in the first quarter of 2025.

KAGRA recovered the power-recycled Fabry-Perot Michelson configuration with a DC readout, including a mirror alignment control system. Although a 6.4 magnitude earthquake struck near the KAGRA site again on 26 November 2024, KAGRA could be recovered within one week. Noise hunting is ongoing; displacement noise has been partially improved from that of O4a. The laser input to the main interferometer is planned to be increased to 10 W to reduce shot noise, in order to improve sensitivity in the high-frequency range. We expect to rejoin the observing run before the end of O4 with a sensitivity of around 10 Mpc.

The planned end date for O4 is 9 June 2025 (no change from the last update). LIGO, Virgo and KAGRA (LVK) are continually assessing planned commissioning and upgrade activities. Should there be any changes to the current planning, we would communicate them here as soon as they are adopted by the LVK.

For more information, see:

OpenMMA wiki - https://github.com/scimma/openMMA/wiki IGWN public alert user guide - https://emfollow.docs.ligo.org/userguide/

Timeline

The gravitational-wave observing schedule is divided into Observing Runs, down time for construction and commissioning, and transitional Engineering Runs between commissioning and observing runs. The current best understanding of the long-term observing schedule is shown below (or https://dcc.ligo.org/LIGO-G2002127/public). Since BNS (Binary Neutron Star) mergers are a well-studied class of gravitational-wave signals, this figure gives the BNS range for for a single-detector SNR threshold of 8 in each observing run.

Long-term observing schedule

The O5 start dates, duration, and sensitivities are current best guesses, and will likely be adjusted as we approach that run for all the detectors (see text).

Live Status

A public web page that report live status of the LIGO/Virgo detectors and alert infrastructure is at

– Page Design adapted from the LIGO/Virgo/KAGRA Public Alerts User Guide –