TITLE: GCN CIRCULAR NUMBER: 24522 SUBJECT: LIGO/Virgo S190513bm: Identification of a GW compact binary merger candidate DATE: 19/05/13 21:37:24 GMT FROM: Marco Drago at GSSI The LIGO Scientific Collaboration and the Virgo Collaboration report: We identified the compact binary merger candidate S190513bm during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2019-05-13 20:54:28.747 UTC (GPS time: 1241816086.747). The candidate was found by the GstLAL [1], CWB [2], MBTAOnline [3], and spiir [4] analysis pipelines. S190513bm is an event of interest because its false alarm rate, as estimated by the online analysis, is 3.7e-13 Hz, or about one in 1e5 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S190513bm The classification of the GW signal, in order of descending probability, is BBH (94%), MassGap (5%), NSBH (<1%), Terrestrial (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, there is strong evidence against the lighter compact object having a mass < 3 solar masses (HasNS: <1%). Using the masses and spins inferred from the signal, there is strong evidence against matter outside the final compact object (HasRemnant: <1%). One skymap is available at this time and can be retrieved from the GraceDB event page: * bayestar.fits.gz, an updated localization generated by BAYESTAR [5], distributed via GCN notice about 27 minutes after the candidate For the bayestar.fits.gz skymap, the 90% credible region is 691 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1987 +/- 501 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] Messick et al. PRD 95, 042001 (2017) [2] Klimenko et al. PRD 93, 042004 (2016) [3] Adams et al. CQG 33, 175012 (2016) [4] Qi Chu, PhD Thesis, The University of Western Australia (2017) [5] Singer & Price PRD 93, 024013 (2016)