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GCN Circular 36260

Subject
LIGO/Virgo/KAGRA S240421ar: Updated Sky localization
Date
2024-04-23T18:41:46Z (25 days ago)
From
Elise Sänger at Max Planck Institute for Gravitational Physics (AEI Potsdam) <elise.sanger@ligo.org>
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), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S240421ar (GCN Circular 36205). This candidate from a weakly modeled CBC search was previously erroneously referred to as "unmodeled transient". 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/S240421ar

For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is 2601 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 7702 +/- 2899 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
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