TITLE:   GCN CIRCULAR
NUMBER:  36348
SUBJECT: LIGO/Virgo/KAGRA S240426s: Updated Sky localization
DATE:    24/04/29 18:28:27 GMT
FROM:    Sylvia Biscoveanu at Northwestern CIERA <sylvia.biscoveanu@ligo.org>

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

We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S240426s (GCN Circular 36312). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page:

https://gracedb.ligo.org/superevents/S240426s

For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is 3050 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3452 +/- 1295 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