Black Hole - Neutron Star merger alert (especially for Australia)

American Association of Variable Star Observers (AAVSO)
Tue, 04/23/2024 - 07:41

This is especuially of interest for Australian observers right now as the night starts on the East coast soon:


For a prioritized list of target galaxies to observe, go to and select "S240422ed" from the drop down list

This is most likely a merger between a black hole and a neutron star, which could in theory (unlike a black hole - black hole merger) result in an observable optical transient, even tho the distance (188 +/- 43 Mpc) is still high for amateurs, nut we can try... The chance that this is a false alert is ver very low, so at least it is an actual event.

The event is relatively well localized in the sky, in a patch that is centered around roughly RA 8h and Dec -30 deg, so well suited for Australia & Chile  but still visible from sites more to the north.

Good luck!!