S231226av: a well-localized binary black hole merger


Mergers of binary objects like black holes are notoriously difficult to pinpoint on the sky when observing them with gravitational wave interferometers. Today, the two LIGO observatories detected and located S231226av, a binary black hole merger at a distance of 1218 ± 171 Mpc. Although only detected by two interferometers (VIRGO is not taking data), the event was well localized to a region spanning only 54 deg² at 50% containement and 196 deg² at 90%.