[vsnet-grb-info 28243] IceCube-210629A: Upper limits from Fermi-GBM Observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  30346
SUBJECT: IceCube-210629A: Upper limits from Fermi-GBM Observations
DATE:    21/06/30 17:11:47 GMT
FROM:    Joshua Wood at MSFC/Fermi-GBM  <joshua.r.wood at nasa.gov>

J. Wood (NASA/MSFC) reports on behalf of the Fermi-GBM Team:

For the IceCube high-energy neutrino candidate event IceCube-210629A (GCN 30342),
at the event time Fermi-GBM was observing the reported neutrino location at:

RA: 340.75 (+1.11 -2.23 deg  90% PSF containment) J2000
Dec: +12.94 (+0.91 -0.93 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-210629A.

We set upper limits on impulsive gamma-ray emission. Using the
representative soft, normal, and hard GRB-like templates
(arXiv:1612.02395), we report 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      8.3        18.
1.024 s:   1.3      2.4        5.0
8.192 s:   0.5      0.9        1.8

These results are preliminary.