{
  "bibcode": "2020GCN.26728....1G",
  "body": "S. Garrappa (DESY-Zeuthen), S. Buson (Univ. of Wuerzburg) and V. Paliya \n(DESY-Zeuthen)�on behalf of the Fermi-LAT collaboration:\n\nWe report an analysis of observations of the vicinity of the high-energy \nIC200109A neutrino event (GCN 26696) 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 2020-01-09 at 23:41:39.94 \nUT (T0) with J2000 position RA = 164.49 (+4.94, -4.19) deg, Decl. = \n11.87 (+1.16, -1.36) deg 90% PSF containment. Two cataloged >100 MeV \ngamma-ray sources (The Fermi-LAT Collaboration 2019, \narXiv:1902.10045)�are located within the 90% IC200109A localization \nerror. These are the objects 4FGL J1103.0+1157 and 4FGL J1114.6+1225. \nBased on a preliminary analysis of the LAT data over the timescales of \n1-day and 1-month prior to T0, these objects are not significantly \ndetected at gamma-rays.\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 (> 5 sigma) new excess emission (> 100 \nMeV), at the IC200109A 90% 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 < \n4e-10 ph cm^-2 s^-1 for ~11-years (2008-08-04 / 2020-01-09 UTC), < 8e-9 \n(< 7e-8) ph cm^-2 s^-1 for a 1-month (1-day) integration time before T0.\n\nWithin the error circle for the direction of the neutrino, ~1.2deg \noffset from the best-fit IC200109A position, a ~4 sigma excess of gamma \nrays, Fermi J1055.8+1034�was detected in an analysis of the integrated \nLAT data (> 100 MeV) between 2008-08-04 and �2020-01-09.�Assuming a \npower-law spectrum,�the�best-fit�localization is (J2000) \nRA:��163.97,�Dec: 10.58 (0.19 deg 99% containment,�0.09 deg \n68%�containment), with best-fit spectral parameters flux =�(1.6 +/- \n0.8)e-9 ph cm^-2 s^-1 and index = 2.06 +/- 0.18. In a preliminary \nanalysis of the LAT data over one day and one month prior T0, Fermi \nJ1055.8+1034� is not significantly detected in the LAT data.\n\nSince Fermi normally operates in an all-sky scanning mode, regular \nmonitoring of this source will continue. For these sources the Fermi-LAT \ncontact persons are S. Garrappa (simone.garrappa at desy.de \n<http://desy.de/>) and S. Buson (sara.buson at uni-wuerzburg.de \n<http://uni-wuerzburg.de/>). The Fermi LAT is a pair conversion \ntelescope designed to cover the energy band from 20 MeV to greater than \n300 GeV. It is the product of an international collaboration between \nNASA and DOE in the U.S. and many scientific institutions across France, \nItaly, Japan and Sweden.",
  "circularId": 26728,
  "createdOn": 1578909293000,
  "email": "simone.garrappa@desy.de",
  "subject": "Fermi-LAT Gamma-ray Observations of IceCube-200109A and detection of a possible new gamma-ray source, Fermi J1055.8+1034",
  "submitter": "Simone Garrappa at DESY  <simone.garrappa@desy.de>",
  "eventId": "IceCube-200109A"
}