TITLE: GCN CIRCULAR NUMBER: 28884 SUBJECT: Fermi-LAT Gamma-ray Observations of NuEm-201107A DATE: 20/11/12 21:16:07 GMT FROM: Simone Garrappa at DESY S. Garrappa (DESY-Zeuthen) and S. Buson (Univ. of Wuerzburg) on behalf of the Fermi-LAT collaboration: We report an analysis of observations of the vicinity of the IceCube-HAWC coincidence alert (GCN 28865) with all-sky survey data from the Large Area Telescope (LAT), on board the Fermi Gamma-ray Space Telescope. The HAWC event was detected in a 6.42 hours interval from  2020-11-07 at 09:29:47 UT and 2020-11-07 at 15:55:31 UT with J2000 position RA = 140.20  deg, Decl. = 29.76 deg  and a 90% PSF containment of 0.271 deg . No cataloged >100 MeV gamma-ray sources (The Fourth Fermi-LAT catalog; The Fermi-LAT collaboration 2020, ApJS, 247, 33) are located within the 90% NuEm-201107A localization error. We searched for short (hours to day) timescale emission from a new gamma-ray transient source. Preliminary analysis indicates no significant (> 5 sigma) new excess emission (> 100 MeV) at the NuEm-201107A best-fit position. Assuming a power-law spectrum (photon index = 2.0 fixed) for a point source at the NuEm-201107A best-fit position, the >100 MeV flux upper limit (95% confidence) is < 1.5e-7 ph cm^-2 s^-1 for ~6.4 hours, < 5.5e-8  ph cm^-2 s^-1 for a 1-day integration time before 2020-11-07 at 15:55:31 UT. Since Fermi normally operates in an all-sky scanning mode, regular monitoring of this source will continue. For these observations the Fermi-LAT contact persons are S. Garrappa (simone.garrappa 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.