TITLE:   GCN CIRCULAR
NUMBER:  26676
SUBJECT: Fermi-LAT ANTARES coincidence: Upper limits from Fermi-GBM Observations
DATE:    20/01/08 22:56:03 GMT
FROM:    Joshua Wood at MSFC/Fermi-GBM  <joshua.r.wood@nasa.gov>

J. Wood (NASA/MSFC) reports on behalf of the Fermi-GBM Team:

For the Fermi-LAT ANTARES coincidence event on 2020 January 8th (GCN 26674), at the event time Fermi-GBM was observing the reported location at:

RA:  02:53:55.6 (J2000)
Dec: -18:04:02 (J2000)
r_90:  0.832 deg (90%-containment)

There was no Fermi-GBM onboard trigger around the event time of the concidence event. An automated, blind search for short gamma-ray bursts below the onboard triggering threshold in Fermi-GBM also identified no counterpart candidates. The GBM targeted search, the most sensitive, coherent search for GRB-like signals, was run from 30 s before the identified neutrino event at 09:25:12 UT until 30 seconds after the detection of the Fermi LAT photon at 09:35:16.96 UT. From this search, no significant signal was found related to the reported location.

We set upper limits on impulsive gamma-ray emission. Using the representative soft, normal, and hard GRB-like templates described in arXiv:1612.02395, we set the following 3 sigma flux upper limits over 10-1000 keV (in units of 10^-6 erg/s/cm^2):

Timescale  Soft     Normal   Hard
--------------------------------------
0.128 s:   6.7      12.      21.
1.024 s:   1.7      2.5      5.0
8.192 s:   0.7      1.1      1.7