TITLE: GCN CIRCULAR NUMBER: 27229 SUBJECT: LIGO/Virgo S200225q: Updated Sky Localization DATE: 20/02/26 20:40:15 GMT FROM: Leo Singer at GSFC The LIGO Scientific Collaboration and the Virgo 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 S200225q (GCN Circular 27193). Parameter estimation has been performed using LALInference [1] and a new sky map, LALInference.fits.gz,1, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S200225q The original localization in GCN 27193 only used data from H1 and L1. This updated localization uses data from H1, L1, and V1. The preferred sky map at this time is LALInference.fits.gz,1. For the LALInference.fits.gz,1 sky map, the 90% credible region is well fit by an ellipse with an area of 27 deg2 described by the following DS9 region (right ascension, declination, semi-major axis, semi-minor axis, position angle of the semi-minor axis): icrs; ellipse(08h28m26s, +87d45m51s, 3.38d, 2.54d, 104.41d) Marginalized over the whole sky, the a posteriori luminosity distance estimate is 995 +/- 188 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo Public Alerts User Guide . [1] Veitch et al. PRD 91, 042003 (2015)