TITLE:   GCN CIRCULAR
NUMBER:  34606
SUBJECT: LIGO/Virgo/KAGRA S230831e: Updated Sky localization
DATE:    23/08/31 12:41:35 GMT
FROM:    Soichiro Morisaki at U. of Tokyo <soichiro.morisaki@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 S230831e (GCN Circular 34605).
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/S230831e

For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible
region is 3803 deg2. Marginalized over the whole sky, the a posteriori
luminosity distance estimate is 4900 +/- 2126 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/userguide/.


 [1] Ashton et al. ApJS 241, 27 (2019)