{
  "bibcode": "2022GCN.33100....1G",
  "body": "S. Garrappa (Ruhr-Universitaet Bochum), S. Buson (Univ. of Wuerzburg) \nand J. Sinapius (DESY-Zeuthen) on behalf of the Fermi-LAT collaboration:\n\nWe report an analysis of observations of the vicinity of the IC221223A \nhigh-energy neutrino event (GCN 33094) 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 2022-12-23 at 07:43:00.52 \nUT (T0) with J2000 position RA = 350.54 (+0.67, -0.67) deg, Decl. = \n+34.71 (+0.67, -0.67) deg (90% PSF containment). One cataloged gamma-ray \n(>100 MeV) source is located within the 90% IC221223A localization \nregion. This is 4FGL J2322.7+3436 (4FGL-DR3; The Fermi-LAT collaboration \n2022, ApJS, 260, 53), associated with the BL Lac object TXS 2320+343 \n(a.k.a. 5BZB J2322+3436, Massaro et al. 2015, Ap&SS, 357, 1). Based on a \npreliminary analysis of the LAT data over the timescales of 1-day and \n1-month prior to 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 IC221223A \nbest-fit position. Assuming a power-law spectrum (photon index = 2.0 \nfixed) for a point source at the IC221223A best-fit position, the >100 \nMeV flux upper limit (95% confidence) is < 2.1e-10 ph cm^-2 s^-1 for \n~14-years (2008-08-04 to 2022-12-23 UTC), and < 1e-8 (<2.7e-7) ph cm^-2 \ns^-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 region will continue. For these observations the \nFermi-LAT contact persons are S. Garrappa (simone.garrappa at \nruhr-uni-bochum.de), J. Sinapius (jonas.sinapius at desy.de) and S. \nBuson (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": 33100,
  "createdOn": 1671935372000,
  "email": "simone.garrappa@desy.de",
  "subject": "Fermi-LAT gamma-ray observations of IceCube-221223A",
  "submitter": "Simone Garrappa at DESY  <simone.garrappa@desy.de>",
  "eventId": "IceCube-221223A"
}