{
  "bibcode": "2017GCN.21431....1L",
  "body": "The LIGO Scientific Collaboration and the Virgo Collaboration report:\n\nThe gstlal CBC analysis identified candidate G296853 during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2017-08-09 08:28:21.747 UTC (GPS time: 1186302519.747). Virgo (V1) was observing at the time, but with a range only one quarter of that of L1, and data from V1 was not used when estimating this event�s significance.\n\nG296853 is an event of interest because its false alarm rate, as determined by the online analysis, is 7.51e-09 Hz or about one in 4 years, passing our stated alert threshold of ~1/month. The event's properties can be found at this URL:\n\nhttps://gracedb.ligo.org/events/G296853\n\nThis event was also identified in real-time by two other pipelines: Coherent WaveBurst (cWB) and Multi-Band Template Analysis (MBTA).\n\nA sky map is available at this time and can be retrieved from the GraceDB event page:\n * bayestar.fits.gz, a localization generated by BAYESTAR, distributed via GCN notice about 40 minutes after the event. At this time, the BAYESTAR map only uses information from H1 and L1. The 50% credible region spans about 316 deg2 and the 90% region about 1155 deg2, and the posterior probability is mostly confined to the Southern Hemisphere. The mean posterior distance is about 1 Gpc.\n\nThe event appears consistent with the merger of two black holes at this time, and there is little chance either component was a neutron star.\n\nUpdates on our analysis of this event, including updated localizations which include Virgo data, will be sent as they become available.",
  "circularId": 21431,
  "createdOn": 1502274585000,
  "email": "ressick@mit.edu",
  "subject": "LIGO/Virgo G296853: Identification of a GW Binary Merger Candidate",
  "submitter": "Reed Clasey Essick at MIT  <ressick@mit.edu>",
  "eventId": "LIGO/Virgo G296853"
}