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GCN Circular 35144

Subject
LIGO/Virgo/KAGRA S231118d: Updated Sky localization and Source Classification
Date
2023-11-20T20:56:32Z (3 months ago)
From
jgolomb@caltech.edu
Via
Web form
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 S231118d (GCN Circular 35090). 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/S231118d

After parameter estimation by RapidPE-RIFT [2], the updated classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%).

For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 956 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2110 +/- 585 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) and Morisaki et al. arXiv:2307.13380 (2023)
 [2] Rose et al. arXiv:2201.05263 (2022) and Pankow et al. PRD 92, 023002 (2015)
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