{
  "bibcode": "2021GCN.29995....1G",
  "body": "S. Garrappa (DESY-Zeuthen), S. Buson (Univ. of Wuerzburg) and C. C. \nCheung (Naval Research Laboratory) on behalf of the Fermi-LAT collaboration:\n\nWe report an analysis of observations of the vicinity of the high-energy \nIC210510A neutrino event (GCN 29976) with all-sky survey data from the \nLarge Area Telescope (LAT), on board the Fermi Gamma-ray Space \nTelescope. The IceCube event was detected on 2021-05-10 at 04:50:10.73 \nUT (T0) with J2000 position RA = 268.42 (+1.47, -1.60) deg, Decl. = 3.81 \n(+0.68, -0.64) deg (90% PSF containment). One cataloged >100 MeV \ngamma-ray source is located within the 90% IC210510A localization \nregion. This is 4FGL J1747.6+0324 (4FGL-DR2, The Fermi-LAT collaboration \n2020, ApJS, 247, 33), of unknown association. Based on a preliminary \nanalysis of the LAT data over the timescales of 1-day and 1-month prior \nto T0, this object is not significantly detected (> 5 sigma).\n\nWe searched for intermediate (days to years) timescale emission from a \nnew gamma-ray transient source. Preliminary analysis indicates no \nsignificant (> 5 sigma) new excess emission (> 100 MeV) at the IC210510A \nbest-fit position. Assuming a power-law spectrum (photon index = 2.0 \nfixed) for a point source at the IC210510A best-fit position, the >100 \nMeV flux upper limit (95% confidence) is < 6.3e-10 ph cm^-2 s^-1 for \n~12-years (2008-08-04 to 2021-05-10 UTC), and < 6.1e-9 (< 1.8e-7) ph \ncm^-2 s^-1 for a 1-month (1-day) integration time before T0.\n\nSince Fermi normally operates in an all-sky scanning mode, regular \nmonitoring of this source will continue. For these observations the \nFermi-LAT contact persons are S. Garrappa (simone.garrappa at desy.de) \nand S. Buson (sara.buson at uni-wuerzburg.de).\n\nThe Fermi-LAT is a pair conversion telescope designed to cover the \nenergy band from 20 MeV to greater than 300 GeV. It is the product of an \ninternational collaboration between NASA and DOE in the U.S. and many \nscientific institutions across France, Italy, Japan and Sweden.",
  "circularId": 29995,
  "createdOn": 1620768198000,
  "email": "simone.garrappa@desy.de",
  "subject": "Fermi-LAT Gamma-ray Observations of IceCube-210510A",
  "submitter": "Simone Garrappa at DESY  <simone.garrappa@desy.de>",
  "eventId": "IceCube-210510A"
}