GCN Circular 27655
Subject
IceCube-200425A: Upper limits from Fermi-GBM Observations
Event
Date
2020-04-27T16:31:54Z (5 years ago)
From
Cori Fletcher at USRA <cfletcher@usra.edu>
C. Fletcher (USRA) reports on behalf of the Fermi-GBM team:
For the IceCube high-energy neutrino candidate event IceCube-200425A
(GCN 27651), at the event time Fermi-GBM was observing the reported
neutrino location at:
RA: 100.10 (+4.67/-3.14 deg 90% PSF containment) J2000
Dec: 53.57 (+2.45/-1.60 deg 90% PSF containment) J2000
There was no Fermi-GBM onboard trigger around the event time of the
neutrino candidate. An automated, blind search for short gamma-ray
bursts below the onboard triggering threshold in Fermi-GBM identified
a low reliability event 8.93 minutes before IceCube-200425A
(https://gcn.gsfc.nasa.gov/notices_gbm_sub/609549478.fermi). However
due to the temporal offset and low reliability, we do not consider these
two events associated.
The GBM targeted search, the most sensitive, coherent search for GRB-like
signals, was run from +/-30 s around the neutrino candidate time.
From this search, no significant signal was found related
to IceCube-200425A.
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^-7 erg/s/cm^2):
Timescale Soft Normal Hard
-------------------------------------------
0.128 s: 7.3 14. 37.
1.024 s: 2.6 3.9 10.
8.192 s: 0.8 1.8 3.5
These results are preliminary.