TITLE:   GCN CIRCULAR
NUMBER:  36581
SUBJECT: LIGO/Virgo/KAGRA S240531bp: Updated Sky localization
DATE:    24/05/31 15:23:15 GMT
FROM:    Charlie Hoy at University of Portsmouth <charlie.hoy@port.ac.uk>

The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report:

We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S240531bp (GCN Circular 36580). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page:

https://gracedb.ligo.org/superevents/S240531bp

For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 1323 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3766 +/- 1491 Mpc (a posteriori mean +/- standard deviation).

For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/.

 [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380