TITLE: GCN CIRCULAR NUMBER: 19817 SUBJECT: Fermi GBM Observations of IceCube-160806A DATE: 16/08/18 00:12:24 GMT FROM: Eric Burns at U of Alabama E. Burns (UAH), A. Goldstein (USRA), P. Jenke (UAH) and L. Blackburn (CfA) report on behalf of the Fermi GBM team: We have searched the Fermi Gamma-ray Burst Monitor data for a gamma-ray counterpart to the IceCube neutrino 160806A (Cowen 2016, GCN 19787). The location of the neutrino was observed by GBM with good geometry. The closest on-board trigger was more than 90 minutes after the neutrino time and came from a different position on the sky. Measurements using the Earth Occultation technique (Wilson-Hodge et al. 2012, ApJS, 201, 33) around this position place a three sigma flux upper limit of about 160 mCrab between 12 and 100 keV between August 5th and 7th. A seeded search for impulsive emission with duration 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 30 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 looking for events between 0.1 s and 32 s durations 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.). There is some flaring activity from Vela X-1 around the time of interest, most notably around T0+500 seconds. This is unrelated. With no impulsive emission found we set model-dependent 1 second peak flux 3 sigma upper limits on prompt emission. Using a cutoff power law model with index -0.42 and Epeak of 566 keV, representative of a typical short GRB, the limit in the 10-1000 keV range is 9.3x10^-7 erg/cm^2/s. The INTEGRAL SPI-ACS found four intervals of burst-like excesses (Savchenko 2016, GCN 19789). Both the Sun and the neutrino location were occulted by the Earth for Fermi for the first interval. We found no evidence for the other three burst-like excesses in any detectors. Combining the SPI-ACS detection with the GBM non-detection for these three times allows us to infer that these SPI-ACS bursts are most likely due to a source occulted by the Earth for Fermi rather than a solar or neutrino source origin.