{
  "bibcode": "2021GCN.30978....1G",
  "body": "S. Garrappa (DESY-Zeuthen), S. Buson (Univ. of Wuerzburg) and R. de \nMenezes (Univ. of Wuerzburg, Univ. of Sao Paulo) on behalf of the \nFermi-LAT collaboration:\n\nWe report an analysis of observations of the vicinity of the high-energy \nIC211023A neutrino event (GCN 30957) 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 2021-10-23 at 08:31:18.31 \nUT (T0) with J2000 position RA = 253.30 (+1.05,-1.08) deg, Decl. = -1.72 \n(+1.16, -1.11) deg (90% PSF containment). One cataloged gamma-ray (>100 \nMeV) source is located within the 90% IC211023A localization region. \nThis is 4FGL J1653.6-0158 (4FGL-DR2, The Fermi-LAT collaboration 2020, \nApJS, 247, 33), identified as PSR J1653-0158 (Nieder et al. 2020 ApJL \n202, 46). Based on a preliminary analysis of the LAT data over the \ntimescales of 1-day and 1-month prior to T0, this object is not \nsignificantly 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 IC211023A \nbest-fit position. Assuming a power-law spectrum (photon index = 2.0 \nfixed) for a point source at the IC211023A best-fit position, the >100 \nMeV flux upper limit (95% confidence) is < 8.8e-10 ph cm^-2 s^-1 for \n~13-years (2008-08-04 to 2021-10-23 UTC), and < 1.6e-8 (< 1.9e-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": 30978,
  "createdOn": 1635108639000,
  "email": "simone.garrappa@desy.de",
  "subject": "Fermi-LAT Gamma-ray Observations of IceCube-211023A",
  "submitter": "Simone Garrappa at DESY  <simone.garrappa@desy.de>",
  "eventId": "IceCube-211023A"
}