TITLE: GCN CIRCULAR NUMBER: 19364 SUBJECT: IceCube-160427A: Fermi GBM Observations DATE: 16/04/29 21:08:30 GMT FROM: Eric Burns at U of Alabama Lindy Blackburn (CfA), Michael S. Briggs (UAH), Eric Burns (UAH), Jordan Camp (NASA/GSFC), Tito Dal Canton (NASA/GSFC), Nelson Christensen (Carleton College), Valerie Connaughton (USRA), Adam Goldstein (NASA/MSFC), C. M. Hui (NASA/MSFC), Peter Jenke (UAH), Tyson Littenberg (UAH), Judith Racusin (NASA/GSFC), Peter Shawhan (UMD), Leo Singer (NASA/GSFC), John Veitch (Birmingham), Colleen Wilson-Hodge (NASA/MSFC), and Binbin Zhang (IAA-CSIC) We have searched the Fermi Gamma-ray Burst Monitor data for a gamma-ray counterpart for the IceCube High Energy Starting Event (HESE) 67093193, detected in run 127853 on 2016-04-27 05:52:32.00 UT (AMON GCN notice rev. 2, http://gcn.gsfc.nasa.gov/notices_amon/67093193_127853.amon. See http://gcn.gsfc.nasa.gov/doc/Public_Doc_AMON_IceCube_GCN_Alerts_v2.pdf for a description of HESE events and related GCN notices). The location of the neutrino was close to the Earth, but visible at event time. There were no on-board triggers in GBM near the time of the neutrino detection. We searched for associated gamma-ray emission with 3 different search techniques. A seeded search for impulsive emission with durations between 0.256 s and 8.192 s around the time and sky location of the detected neutrino yielded no candidates above the GBM background. The search method was developed to look for electromagnetic counterparts in the GBM data of sub-threshold gravitational wave signals found in the LIGO data (Blackburn et al. 2015, ApJS, 217, 8), and implemented here searching from 30 s before to 90 s after and seeded with the position of the detected neutrino. A blind search for untriggered impulsive emission in the GBM data centered on the neutrino detection yielded no candidates consistent with the position of the neutrino. This search technique was developed for the detection of untriggered short GRBs in the GBM data (Briggs et al., in prep.). Measurements using the Earth Occultation technique (Wilson-Hodge et al. 2012, ApJS, 201, 33) using the IceCube position in 17.5 hours around the neutrino detection place a three sigma flux limit of 224 mCrab between 12 and 300 keV.