{
  "bibcode": "2019GCN.24583....1A",
  "body": "M. Axelsson (KTH and Stockholm Univ.), F. Longo (Univ. and INFN Trieste),\nN. Omodei (Stanford) and D. Kocevski (NASA/MSFC) report on behalf of the\nFermi-LAT Collaboration:\n\nWe have searched data collected by the Fermi Large Area Telescope (LAT) on\nMay 17, 2019, for possible high-energy (E > 100 MeV) gamma-ray emission in\nspatial/temporal coincidence with the LIGO/Virgo trigger S190517h (GCN\n24570).\n\nWe define \"instantaneous coverage\" as the integral over the region of the\nLIGO\nprobability map that is within the LAT field of view at a given a time, and\n\"cumulative coverage\" as the integral of the instantaneous coverage over\ntime. Fermi-LAT had instantaneous coverage of ~35% of the LIGO probability\nat the time of the trigger (T0 = 2019-05-17 05:51:01.83 UTC), and reached\n100% cumulative coverage after ~7.1ks.\n\nWe performed a search for a transient counterpart within the observed\nregion of\nthe 90% contour of the LIGO map in a fixed time window from T0 to T0 + 10\nks.\nNo significant sources were found.\n\nWe also performed a search which adapted the time interval of the analysis\nto the exposure of each region of the sky, and no additional excesses were\nfound.\n\nEnergy flux upper bounds for the fixed time interval between 100 MeV and 1\nGeV\nfor this search vary between 1.7e-10 and 4.0e-09 [erg/cm^2/s].\n\nThe Fermi-LAT point of contact for this event is Magnus Axelsson (\nmagaxe@kth.se).\n\nThe Fermi-LAT is a pair conversion telescope designed to cover\nthe energy band from 20 MeV to greater than 300 GeV\nIt is the product of an international collaboration between\nNASA and DOE in the U.S. and many scientific institutions\nacross France, Italy, Japan and Sweden.",
  "circularId": 24583,
  "createdOn": 1558114050000,
  "email": "franzlongo1969@gmail.com",
  "subject": "LIGO/Virgo S190517h: Fermi-LAT search for a high-energy gamma-ray counterpart",
  "submitter": "Francesco Longo at U of Trieste,INFN Trieste  <franzlongo1969@gmail.com>",
  "eventId": "LIGO/Virgo S190517h"
}