LIGO/Virgo S190728q: Update on SkyLocalization and SourceClassification
Abstract
We have conducted further analysis of the LIGO and Virgo data around the time of the compact binary coalescence (CBC) candidate S190728q (GCN 25187). Parameter estimation has been performed using LALInference [1] and a new sky map, LALInference.offline.fits.gz, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S190728q/ LALInference.offline.fits.gz is the preferred sky map at this time. The 90% credible region is 104 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 874 +/ 171 Mpc (a posteriori mean +/ standard deviation). Based on posterior support from parameter estimation [1,2], under the assumption that the candidate S190728q is astrophysical in origin, there is strong evidence against the hypothesis that the lighter compact object has a mass < 3 solar masses (HasNS < 1%) and a negligible probability of having disrupted material outside the final compact object (HasRemnant < 1%). The parameter estimation based classification of the GW signal, in order of descending probability, is BBH (95%), MassGap (5%), NSBH (<1%), or BNS (<1%). The above mentioned probabilities are based on full exploration of the binary parameter space, and hence are the preferred classification results that supersede the ones stated in GCN 25187. The probability of nonastrophysical origin and the false alarm rate are not being updated at this time; both measures of significance should be expected to change with offline analyses and continued observations. 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) [2] Abbott, et al. PRL 116, 241102 (2016)
 Publication:

GRB Coordinates Network
 Pub Date:
 July 2019
 Bibcode:
 2019GCN.25208....1L