GCN Circular 31256
Subject
IceCube-211216B: Upper limits from Fermi-GBM Observations
Date
2021-12-18T00:23:20Z (3 years ago)
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 IceCube high-energy neutrino candidate event IceCube-211216B
(GCN 31249), at the event time Fermi-GBM was observing the reported
neutrino location at:
RA: 199.34 (+1.66/-1.78 deg 90% PSF containment) J2000
Dec: 17.04 (+1.39/-1.36 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-211216B.
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: 5.2 8.2 16.
1.024 s: 1.4 2.3 4.7
8.192 s: 0.4 0.7 2.1
These results are preliminary.