Fermi-LAT gamma-ray observations of IceCube-230122A

We report an analysis of observations of the vicinity of the IC230122A high-energy neutrino event (GCN 33204) with all-sky survey data from the Large Area Telescope (LAT), on board the Fermi Gamma-ray Space Telescope. The IceCube event was detected on 2023-01-22 at 03:50:02.00 UT (T0) with J2000 position RA = 16.79 (+3.17, -2.56) deg, Decl. = +7.78 (+3.44, -3.26) deg (90% PSF containment). Five cataloged gamma-ray (>100 MeV; The Fermi-LAT collaboration 2022, ApJS, 260, 53) sources are located within the 90% IC230122A localization region. Based on a preliminary analysis of the LAT data over the timescales of 1-month prior to T0, one of these objects, the source 4FGL J0100.3+0745 associated to the BL Lac object GB6 J0100+0745 (at 1.68 deg offset from the best-fit neutrino localisation), is detected at ~4 sigma level. The flux measured for the source, is however consistent with the average value measured in the 4FGL. We searched for intermediate (days to years) timescale emission from a new gamma-ray transient source. Preliminary analysis indicates no significant (> 5 sigma) new excess emission (> 100 MeV) at the IC230122A best-fit position. Assuming a power-law spectrum (photon index = 2.0 fixed) for a point source at the IC230122A best-fit position, the >100 MeV flux upper limit (95% confidence) is < 2.9e-10 ph cm^-2 s^-1 for ~14-years (2008-08-04 to 2023-01-22 UTC), and < 6.5e-9 (<1.4e-7) ph cm^-2 s^-1 for a 1-month (1-day) integration time before T0. Since Fermi normally operates in an all-sky scanning mode, regular monitoring of this region will continue. For these observations the Fermi-LAT contact persons are S. Garrappa (simone.garrappa at ruhr-uni-bochum.de), J. Sinapius (jonas.sinapius at desy.de) and S. Buson (sara.buson at uni-wuerzburg.de). The Fermi-LAT is a pair conversion telescope designed to cover the energy band from 20 MeV to greater than 300 GeV. It is the product of an international collaboration between NASA and DOE in the U.S. and many scientific institutions across France, Italy, Japan and Sweden.