[15 March 2022 update; next update by 15 May 2022]

LIGO, Virgo, and KAGRA are closely coordinating to start the O4 Observing run together. We plan to start the O4 Observing run in mid-December 2022, though we are still working through delays resulting from the pandemic. An Engineering Run is planned to start in mid-November; low-latency alerts for candidate events identified during engineering time may be released, both to exercise the system and to preserve the scientific value. We are planning a webinar for late April to update the community about the status of work on the detectors and to discuss the remaining challenges in our current schedule.

LIGO projects a sensitivity goal of 160-190 Mpc for binary neutron stars. Virgo projects a target sensitivity of 80-115 Mpc. KAGRA should be running with greater than 1 Mpc sensitivity at the beginning of O4, and will work to improve the sensitivity toward the end of O4.

The most recent updates are always available at

If you have any questions, please contact the Spokespersons:

  • Patrick Brady (Spokesperson, LIGO Scientific Collaboration)
  • Giovanni Losurdo (Spokesperson, Virgo Collaboration)
  • Jun’ichi Yokoyama (Board Chair, KAGRA Scientific Congress)

(Please replace “_AT_” into “@” and replace “/” into “.” after it.)