GCN Circular 28469
Subject
IceCube-200921A: Upper limits from Fermi-GBM Observations
Event
Date
2020-09-22T02:48:51Z (6 years ago)
From
Rachel Hamburg at UAH <rkh0007@uah.edu>
R. Hamburg (UAH) reports on behalf of the Fermi-GBM team:
For the IceCube high-energy neutrino candidate event IceCube-200921A
(GCN 28468), at the event time Fermi-GBM was observing the reported
neutrino location at:
RA: 195.29 (+2.35 -1.73 deg 90% PSF containment) J2000
Dec: 26.24 (+1.51 -1.77 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 also
identified no counterpart candidates. 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-200921A.
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: 17. 34. 73.
1.024 s: 6.4 13. 21.
8.192 s: 2.2 2.5 1.4
These results are preliminary.