{
  "bibcode": "2019GCN.24377....1L",
  "body": "The LIGO Scientific Collaboration and the Virgo Collaboration report:\n\nWe identified the compact binary merger candidate S190503bf during\nreal-time processing of data from LIGO Hanford Observatory (H1), LIGO\nLivingston Observatory (L1), and Virgo Observatory (V1) at 2019-05-03\n18:54:04.294 UTC (GPS time: 1240944862.294). The candidate was found\nby the GstLAL [1], CWB [2], MBTAOnline [3], PyCBC Live [4], and SPIIR\n[5] analysis pipelines.\n\nS190503bf is an event of interest because its false alarm rate, as\nestimated by the online analysis, is 1.6e-09 Hz, or about one in 19\nyears. The event's properties can be found at this URL:\n\nhttps://gracedb.ligo.org/superevents/S190503bf\n\nThe classification of the GW signal, in order of descending\nprobability, is BBH (96%), MassGap (3%), NSBH (<1%), Terrestrial\n(<1%), or BNS (<1%).\n\nAssuming the candidate is astrophysical in origin, there is strong\nevidence against the lighter compact object having a mass < 3 solar\nmasses (HasNS: <1%). Using the masses and spins inferred from the\nsignal, there is strong evidence against matter outside the final\ncompact object (HasRemnant: <1%).\n\nOne skymap is available at this time and can be retrieved from the\nGraceDB event page:\n* bayestar.fits.gz, an updated localization generated by BAYESTAR\n[6], distributed via GCN notice about 36 minutes after the candidate\n\nFor the bayestar.fits.gz skymap, the 90% credible region is 448 deg2.\nMarginalized over the whole sky, the a posteriori luminosity distance\nestimate is 421 +/- 105 Mpc (a posteriori mean +/- standard\ndeviation).\n\nFor further information about analysis methodology and the contents\nof this alert, refer to the LIGO/Virgo Public Alerts User Guide\n<https://emfollow.docs.ligo.org/userguide/>.\n\n[1] Messick et al. PRD 95, 042001 (2017)\n[2] Klimenko et al. PRD 93, 042004 (2016)\n[3] Adams et al. CQG 33, 175012 (2016)\n[4] Nitz et al. PRD 98, 024050 (2018)\n[5] Qi Chu, PhD Thesis, The University of Western Australia (2017)\n[6] Singer & Price PRD 93, 024013 (2016)\n\n[GCN OPS NOTE(05may19): Per author's request, the redundant \"SUBJECT:\"\nstring was removed from the SUBJECT-line.",
  "circularId": 24377,
  "createdOn": 1556914760000,
  "email": "shaon.ghosh@ligo.org",
  "subject": "LIGO/Virgo S190503bf: Identification of a GW compact binary merger candidate",
  "submitter": "Shaon Ghosh at UWM  <shaon.ghosh@ligo.org>",
  "eventId": "LIGO/Virgo S190503bf"
}