{
  "eventType": [
    "Gamma-ray Transient",
    "Neutrino"
  ],
  "createdOn": 1791898205293,
  "body": "L. Pfeiffer (Univ. of Wuerzburg), S. Buson (DESY, Univ. of Wuerzburg) and S. Garrappa (Weizmann Institute of Science) on behalf of the Fermi-LAT collaboration:\n\nWe report an analysis of observations of the vicinity of the high-energy IC261012A neutrino event (GCN 45929) 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 2026-10-12 at 16:58:11.46 UTC (T0) with J2000 position RA = 177.71 (+0.54, -0.53) deg, Decl. = 8.95 (+0.33, -0.42) deg 90% PSF containment (J2000). No cataloged >100 MeV gamma-ray source is located within the 90% IC261012A localization error (FL16Y, The Fermi-LAT 16 Year Source List, The Fermi-LAT collaboration 2026, arXiv:2602.22148).\n\nWe searched for the existence of intermediate (days to years) timescale emission from a new gamma-ray transient source. Preliminary analysis indicates no significant (>5sigma) new excess emission (> 100 MeV) within the IC261012A 90% confidence localization. Assuming a power-law spectrum (photon index = 2.0 fixed) for a point source at the IC261012A best-fit position, the >100 MeV flux upper limit (95% confidence) is < 2.1e-10 ph cm^-2 s^-1 for ~18-years (2008-08-04 / T0), <3.8e-08 (<1.6e-07) ph cm^-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 monitoring of this source will continue. For this analysis, the Fermi-LAT contact person is L. Pfeiffer (leonard.pfeiffer at uni-wuerzburg.de).\n\nThe 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.",
  "circularId": 45941,
  "format": "text/plain",
  "subject": "Fermi-LAT Gamma-ray Observations of IceCube-261012A",
  "eventId": "IceCube-261012A",
  "submittedHow": "web",
  "submitter": "Leo Pfeiffer at University of Würzburg <pfeiffer.leo@gmail.com>"
}