{
  "bibcode": "2017GCN.20789....1G",
  "body": "Adam Goldstein (USRA) and Colleen Wilson-Hodge (NASA/MSFC) report on behalf\nof the GBM-LIGO Group:\nLindy Blackburn (CfA), Michael S. Briggs (UAH), Jacob Broida (Carleton\nCollege), Eric Burns (UAH), Jordan Camp (NASA/GSFC), Tito Dal Canton\n(NASA/GSFC), Nelson Christensen (Carleton College), Valerie Connaughton\n(USRA), 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)\n\nFermi GBM observed 77% of the LALInference sky map at the time of the LIGO\ntrigger, and we set the following flux upper limits for the entire visible\nsky map (excluded region is a circle with radius of 68 degrees centered on\nRA, Dec = 134.5, +25.6).\n\nUsing a hard Band function with (Epeak, alpha, beta) = (500 keV, -0.5,\n-2.5), we set a 3 sigma, 1-second-averaged flux upper limit for any\ntransient within 30 s of the LIGO trigger time in the 10-1000 keV band\nranging from 5.0e-7 to 1.4e-6 erg/s-cm^2.  Using an exponentially cutoff\npower law parametrized with (Epeak, index) = (566 keV, -0.42), which\nrepresents the average GBM-triggered short GRB, the upper limit ranges from\n5.4e-7 to 1.4e-6 erg/s-cm^2.  The upper limit in the region of the\nAGILE-GRID candidate, AGL J1914+1043 (Tavani et al., GCN 20754), is 5.0e-7\nerg/s-cm^2 using the hard Band function and 5.4e-7 erg/s-cm^2 using the\ncutoff power law.\n\nUsing the Earth Occultation technique (Wilson-Hodge et al. 2012, ApJS, 201,\n33) to estimate the amount of persistent emission during a 48-hour period\ncentered on the LIGO trigger time, we place the following range of 3-sigma\nday-averaged flux upper limits based on observed sources over the entire\nLIGO sky map:\n\nEnergy       min  max  median\n--------------------------------\n 12- 27 keV: 0.08 0.62 0.12 Crab\n 27- 50 keV: 0.14 0.87 0.21 Crab\n 50-100 keV: 0.20 1.27 0.29 Crab\n100-300 keV: 0.39 2.72 0.57 Crab\n300-500 keV: 3.75 28.1 5.58 Crab\n\nThese limits are based on the minimum requirement that each source in the\nEarth Occultation catalog was Earth-occulted at least 6 times in each of\nthe 24 hour periods preceding and following the LIGO trigger and that the\noccultations were well separated from nearby bright sources.",
  "circularId": 20789,
  "createdOn": 1488409308000,
  "email": "adam.michael.goldstein@gmail.com",
  "subject": "LIGO/Virgo G275404: Fermi GBM Upper Limits",
  "submitter": "Adam Goldstein at Fermi/GBM  <adam.michael.goldstein@gmail.com>",
  "eventId": "LIGO/Virgo G275404"
}