{
  "bibcode": "2017GCN.21656....1L",
  "body": "The LIGO Scientific Collaboration and Virgo report:\n\nThe gstlal CBC analysis (Messick et al. Phys. Rev. D 95, 042001, 2017)\nidentified candidate G298936 during real-time processing of data from LIGO\nHanford Observatory (H1) and LIGO Livingston Observatory (L1) at\n2017-08-23 13:13:58.518 UTC (GPS time: 1187529256.518). The Virgo (V1)\ndetector was online but was not included in the analysis because it had\nrecently re-acquired lock. We are investigating the quality of the V1 data\nto determine whether it can be used.\n\nG298936 is an event of interest because its false alarm rate, as\ndetermined by the online analysis, is 1.739e-11 Hz, or about 1 in 1800\nyears. The event's properties can be found at this URL:\n\nhttps://gracedb.ligo.org/events/G298936\n\nThis event was also identified in real-time by two other CBC pipelines,\nPyCBC (Nitz, et al. 2017, arXiv:1705.01513) and MBTA (Adams et al. CQG 33,\n175012, 2016). It was also detected by the unmodeled burst pipelines, cWB\n(Klimenko et al. Phys. Rev. D 93, 042004, 2016) and LIB (Lynch et al.\nPhys. Rev. D 95, 104046, 2017).\n\nThe event appears consistent with the merger of two black holes, and there\nis little chance either component was a neutron star. For more details on\nthe source classification, please consult this technical document:\nhttps://dcc.ligo.org/T1600571/public/main .\n\nA rapid localization with distance information generated by the BAYESTAR\npipeline (e.g., Singer et al. 2016, ApJL 829, 15) is available and can be\nretrieved from the GraceDB event page: bayestar.fits.gz.\n\nThe 50% credible region spans about 605 deg2 and the 90% region about 2145\ndeg2. The probability is concentrated in a pair of long, thin arcs that\nspread across both the northern and southern hemispheres. Marginalized\nover the whole sky, the a posteriori luminosity distance estimate is 1387\n+/- 414 Mpc. It may be possible to improve the localization if the V1 data\ncan be included.\n\nUpdates on our analysis of this event, including updated localizations\nwill be sent as they become available.",
  "circularId": 21656,
  "createdOn": 1503497220000,
  "email": "leo.p.singer@nasa.gov",
  "subject": "LIGO/Virgo G298936: Identification of a GW Binary Black Hole Candidate",
  "submitter": "Leo Singer at NASA/GSFC  <leo.p.singer@nasa.gov>",
  "eventId": "LIGO/Virgo G298936"
}