TITLE: GCN CIRCULAR NUMBER: 24717 SUBJECT: LIGO/Virgo S190602aq: Identification of a GW compact binary merger candidate DATE: 19/06/02 18:36:06 GMT FROM: Peter Shawhan at U of Maryland/LSC The LIGO Scientific Collaboration and the Virgo Collaboration report: We identified the compact binary merger candidate S190602aq during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2019-06-02 17:59:27.089 UTC (GPS time: 1243533585.089). The candidate was found by the PyCBC Live [1], CWB [2], SPIIR [3], GstLAL [4], and MBTAOnline [5] analysis pipelines. S190602aq is an event of interest because its false alarm rate, as estimated by the online analysis, is 1.9e-09 Hz, or about one in 16 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S190602aq The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), BNS (<1%), NSBH (<1%), or MassGap (<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 [6], distributed via GCN notice about 6 minutes after the candidate For the bayestar.fits.gz skymap, the 90% credible region is 1172 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 797 +/- 238 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] Nitz et al. PRD 98, 024050 (2018) [2] Klimenko et al. PRD 93, 042004 (2016) [3] Qi Chu, PhD Thesis, The University of Western Australia (2017) [4] Messick et al. PRD 95, 042001 (2017) [5] Adams et al. CQG 33, 175012 (2016) [6] Singer & Price PRD 93, 024013 (2016)