GCN Circular 31256

Subject

IceCube-211216B: Upper limits from Fermi-GBM Observations

Event

Date

2021-12-18T00:23:20Z (4 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 31249Loading...
 
 ), 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:1612.02395Loading...
 
 , 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.