{
  "bibcode": "2022GCN.31479....1G",
  "body": "S. Garrappa (DESY-Zeuthen), S. Buson (Univ. of Wuerzburg) and J. \nSinapius (DESY-Zeuthen) on behalf of the Fermi-LAT collaboration:\n\nWe report an analysis of observations of the vicinity of the high-energy \nIC220115A neutrino event (GCN 31451) 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 2022-01-15 12:11:39.75 UTC \n(T0) with J2000 position RA = 357.45 (+1.75, -1.18) deg, Decl. = 25.28 \n(+1.03, -0.95) deg 90% PSF containment. No cataloged gamma-ray sources \nare found within the 90% IC220115A localization error (The Fourth \nFermi-LAT catalog DR2; The Fermi-LAT collaboration 2020, ApJS, 247, 33).\n\nWe searched for the existence of intermediate (months to years) \ntimescale emission from a new gamma-ray transient source. Preliminary \nanalysis indicates no significant (>5sigma) new excess emission (> 100 \nMeV) at the the IC220115A best-fit position. Assuming a power-law \nspectrum (photon index = 2.0 fixed) for a point source at the IceCube \nbest-fit position, the >100 MeV flux upper limit (95% confidence) is < \n5.6-10 ph cm^-2 s^-1 for ~13-years (2008-08-04 / 2022-01-15 UTC), < \n1.1e-8 (< 5.2e-8) ph cm^-2 s^-1 for a 1-month (1-day) integration time \nbefore T0.\n\nWithin the 90% confidence localization of the neutrino, ~1.1 deg offset \nfrom the best-fit IC220115A position, a >4 sigma excess of gamma rays, \nFermi J2350.2+2620 was detected in an analysis of the integrated LAT \ndata (> 100 MeV) between 2008-08-04 and 2022-01-15. Assuming a power-law \nspectrum, the candidate gamma-ray source has best-fit localization \n(J2000) RA: 357.564, Dec: 26.343 (0.15 deg 99% containment, 0.07 deg 68% \ncontainment), with best-fit spectral parameters flux = (8 +/- 5)e-10 ph \ncm^-2 s^-1 and index = 2.0 +/- 0.2. In a preliminary analysis of the LAT \ndata over one day and one month prior T0, Fermi J2350.2+2620 is not \nsignificantly detected in the LAT data. All values include the \nstatistical uncertainty only.\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). The Fermi LAT is a pair \nconversion telescope designed to cover the energy band from 20 MeV to \ngreater than 300 GeV. It is the product of an international \ncollaboration between NASA and DOE in the U.S. and many scientific \ninstitutions across France, Italy, Japan and Sweden.",
  "circularId": 31479,
  "createdOn": 1642506024000,
  "email": "simone.garrappa@desy.de",
  "subject": "Fermi-LAT Gamma-ray Observations of IceCube-220115A and detection of a new gamma-ray source, Fermi J2350.2+2620",
  "submitter": "Simone Garrappa at DESY  <simone.garrappa@desy.de>",
  "eventId": "IceCube-220115A"
}