GCN Circular 19364

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.