[vsnet-grb-info 25129] LIGO/Virgo S200225q: Updated Sky Localization

[GCN Circulars]

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  <leo.p.singer at nasa.gov>

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
<https://emfollow.docs.ligo.org/userguide/>.

[1] Veitch et al. PRD 91, 042003 (2015)