[vsnet-grb-info 24589] LIGO/Virgo S200105ae: Updated Sky Localization and EM-Bright Probabilities

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  26688
SUBJECT: LIGO/Virgo S200105ae: Updated Sky Localization and EM-Bright Probabilities
DATE:    20/01/09 18:17:27 GMT
FROM:    Peter Shawhan at U of Maryland/LSC  <pshawhan at umd.edu>

The LIGO Scientific Collaboration and the Virgo Collaboration report:

We have conducted further analysis of the LIGO Livingston Observatory
(L1) and Virgo Observatory (V1) data around the time of the compact
binary merger (CBC) candidate S200105ae (GCN Circulars 26640,
26657). Parameter estimation has been performed using LALInference [1]
and a new sky map, LALInference.fits.gz,0, distributed via GCN Notice,
is available for retrieval from the GraceDB event page:

https://gracedb.ligo.org/superevents/S200105ae

The preferred sky map at this time is LALInference.fits.gz,0. For the
LALInference.fits.gz,0 sky map, the 90% credible region is 7373 deg2.
Marginalized over the whole sky, the a posteriori luminosity distance
estimate is 283 +/- 74 Mpc (a posteriori mean +/- standard deviation).

Based on posterior support from parameter estimation [1], under the
assumption that the candidate S200105ae is astrophysical in origin,
the probability that the lighter compact object has a mass < 3 solar
masses (HasNS) is 98%. Using the masses and spins inferred from the
signal, the probability of matter outside the final compact object
(HasRemnant) is <1%.

There is no change to our assessment of the significance of the
candidate.  As noted in the previous Circulars, our examination of the
data indicates that the signal has greater significance than what was
calculated in real-time processing (and is still contained in the GCN
Notice), sufficient to warrant a public alert.

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)