{
  "bibcode": "2017GCN.20365....1B",
  "body": "E. Burns (UAH) reports on behalf of the GBM-LIGO Group:\nLindy Blackburn (CfA), Michael S. Briggs (UAH), Jacob Broida (Carleton\nCollege), Jordan Camp (NASA/GSFC), Tito Dal Canton (NASA/GSFC), Nelson\nChristensen (Carleton College), Valerie Connaughton (USRA), Adam Goldstein\n(NASA/MSFC), Rachel Hamburg (UAH), C. Michelle Hui (NASA/MSFC), Pete Jenke\n(UAH), Dan Kocevski (NASA/MSFC), Nicolas Leroy (LAL), Tyson Littenberg\n(NASA/MSFC), Julie McEnery (NASA/GSFC), Rob Preece (UAH), Judith Racusin\n(NASA/GSFC), Peter Shawhan (UMD), Karelle Siellez (GA Tech), Leo Singer\n(NASA/GSFC), John Veitch (Birmingham), Peter Veres (UAH), Colleen\nWilson-Hodge (NASA/MSFC)\n\nGBM was observing 82.4% of the initial LIGO BAYESTAR probability map for\nG268556 at event time, with a large part of the southern high probability\nregion occulted by the Earth (specifically, locations within ~67 degrees of\n(RA=297.7, Dec=-25.3)). The closest on-board trigger time was more than 12\nhours earlier and was due to high particle activity on entry to the SAA.\nThe untargeted ground-based SGRB search of GBM data between ten and eleven\nUTC (Briggs et al., in prep) found no candidates around G268556.\n\nThe targeted search of the GBM data ([1], [2]) also did not find a\nsignificant gamma-ray signal. This search processes time scales of 0.265 to\n8.192 s within 30 s of the LIGO event. The most significant candidate was\nfound on the longest timescale with the soft spectral template,\ncorresponding to a false alarm rate of ~0.003 Hz. The 8.192 s window of\nthis candidate begins 5.4 s before the T0 of G268556. The location\nidentified by the search is consistent with the high probability region of\nthe LIGO annulus, with the GBM localization peaking around (130, 10); the\ntargeted search location is marginally consistent with a galactic origin.\nHowever, the signal appears in detectors observing different regions of the\nsky. Further investigation rules out a solar origin. There is longer term\nstructure for tens of seconds in the low energy channels of GBM.\n\nBoth prompt and longer term upper limits will be sent in a forthcoming\ncircular.\n\n\n[1] L. Blackburn et al. 2015, ApjS 217, 8\n[2] A. Goldstein et al. arXiv:1612.02395",
  "circularId": 20365,
  "createdOn": 1483564706000,
  "email": "eb0016@uah.edu",
  "subject": "LIGO/Virgo G268556: Fermi GBM Observations",
  "submitter": "E. Burns at U of Alabama/Huntsville  <eb0016@uah.edu>",
  "eventId": "LIGO/Virgo G268556"
}