{
  "bibcode": "2017GCN.20777....1V",
  "body": "G. Vianello (Stanford), N.Omodei (Stanford), Daniel Kocevski (NASA/MSFC)\nand Sara Buson (GSFC) report on behalf of the Fermi-LAT team:\n\n\nWe have searched data collected by the Fermi Large Area Telescope (LAT)\nfor possible high-energy  (E > 100 MeV) gamma-ray emission in spatial/temporal\ncoincidence with the LIGO/Virgo trigger G275697.\n\nFermi-LAT had an instantaneous coverage of ~20% at the time of the trigger\n(T0 =  2017-02-27 18:57:31.375 UTC), and reached 100% cumulative coverage\nwithin ~7 ks. We define \"instantaneous coverage\" as the integral over the region\nof the LIGO probability map that is within the LAT field of view at a\ngiven time,\nand \"cumulative coverage\" as the integral of the instantaneous coverage over\ntime.\n\nWe performed a search for a transient counterpart within the 90% contour of the\nLIGO map in the time window from T0  to T0 + 10 ks, and no significant new\nsources are found.\n\nWe also performed a search which adapted the time interval of the analysis to\nthe exposure of each region of the sky. No significant candidate counterpart\nwas found.\n\nEnergy flux upper bounds between 100 MeV and 100 GeV for this search vary\nbetween  3e-10 ��� 3e-9 [erg/cm^2/s].\n\nThe Fermi-LAT is a pair conversion telescope designed to cover the energy band\nfrom 20 MeV to greater than 300 GeV. It is the product of an international\ncollaboration between NASA and DOE in the U.S. and many scientific institutions\nacross France, Italy, Japan and Sweden.",
  "circularId": 20777,
  "createdOn": 1488323148000,
  "email": "giacomo.slac@gmail.com",
  "subject": "LIGO/Virgo G275697: Fermi-LAT search for a high-energy gamma-ray counterpart",
  "submitter": "Giacomo Vianello at Stanford U/Fermi LAT  <giacomo.slac@gmail.com>",
  "eventId": "LIGO/Virgo G275697"
}