GCN Circular 30871
Subject
IceCube-210922A: Upper limits from Fermi-GBM Observations
Date
2021-09-23T15:47:11Z (3 years ago)
From
Christian Malacaria at NASA-MSFC/USRA <cmalacaria@usra.edu>
C. Malacaria (USRA) reports on behalf of the Fermi-GBM team:
For the IceCube high-energy neutrino candidate event IceCube-210811A
(GCN 30862), at the event time Fermi-GBM was observing the reported
neutrino location at:
RA: 60.73 (+0.96, -0.66 deg 90% PSF containment) J2000
Dec: -4.18 (+0.42, -0.55 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-210922A.
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 norm hard
--------------------------------------
0.128 s: 6.4 11. 14.
1.024 s: 2.1 3.4 4.6
8.192 s: 0.6 0.9 1.4
These results are preliminary.