GCN Circular 22132
S. Buson (NASA/GSFC), M. Kreter (Wurzburg Univ.), D. Kocevski (NASA/MSFC) report on behalf of the Fermi-LAT collaboration We report follow-up observations of the [very] high-energy IceCube-171106A neutrino event (GCN #22105) 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 2017-1-06 18:39:39.21 UTC (T0) with J2000 position RA =340.25 deg, Dec = 7.314 deg (14.99 arcmin 50% containment). The closest cataloged >100 MeV gamma-ray source is 3FGL J2234.8+0945, at a distance of roughly 2.9 deg. The source is associated with the pulsar PSR J2234+0944. We searched for the existence of intermediate (days to months) timescale emission from a new gamma-ray transient source [or excess emission from a known catalog source]. Preliminary analysis indicates no significant excess gamma-ray emission (0.1 - 300 GeV) within the IceCube-171106A 50% confidence localisation. Assuming a power-law spectrum (photon index = 2.2 fixed) for a point source at the IceCube position, the >100 MeV photon flux upper limits (95% confidence) are < 2.0 x 10^-7 ph cm^-2 s^-1 in one day of exposure prior to T0, and < 3.4 x 10^-8 ph cm^-2 s^-1 in one week of exposure prior to T0, and < 1.8 x 10^-9 ph cm^-2 s^-1 in eight months of exposure prior to T0. Swift-XRT follow up observations of the IceCube-171106A field by Keivani et al (GCN #22115) reported the detection of several X-ray sources. Integrating the LAT data for the time intervals aforementioned, no significant gamma-ray emission is observed consistent with these sources. Because Fermi operates in an all-sky scanning mode, regular gamma-ray monitoring of this source region will continue. For this source the Fermi LAT contact person is S. Buson (email: sara.buson at nasa.gov). 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.