Gravitational wave observations resumed

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Following the break of the observation run O4 in early January (see Gravitational wave observations paused), observations have now resumed. This time all three major interferometers (2 x LIGO + Virgo) are taking data together.
While the official start of this data taking period called O4b is scheduled for April 10, 2024 at 15h UTC, a first, low-significance event has already been recorded jointly be all three detectors (S240404g). The public alert stream has been re-actived during this preparatory phase leading up to the official start and you can thus expect to see the events and notifications in Astro-COLIBRI.

Details of the GW observation plans are available at: IGWN | Observing Plans

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Nicely filling the waiting time for the official start of O4b, the LIGO/Virgo/KAGRA collaboration just announced the detailed analysis of an intriguing event detected last year: GW230529.

“The primary component of this binary has a mass between 2.5 and 4.5 solar masses. The nature of this component is uncertain as its mass is larger than the expected range for neutron stars and smaller than the expected range for black holes. The secondary component has a mass between 1.2 and 2.0 solar masses and is almost certainly a neutron star.” From: https://www.ligo.org/detections/GW230529.php