GCN Circular 24917
Subject
IceCube-190629A: Upper limits from Fermi-GBM Observations
Date
2019-06-30T13:27:38Z (6 years ago)
From
Rachel Hamburg at UAH <rkh0007@uah.edu>
J. Wood (NASA) and R. Hamburg (UAH) report on behalf of the
Fermi-GBM Team:
For the IceCube high-energy neutrino candidate event 190629A
(GCN 24910), at the event time Fermi-GBM was observing the
reported neutrino location at:
RA = 27.22 (Dec value too close to pole for accurate error on RA) J2000
DEC = 84.33 (+4.95/-3.13 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 gamma
-ray transients below the onboard triggering threshold in Fermi-
GBM also identified no counterpart candidates +/- 1 hour of event
time.
The GBM targeted search, the most sensitive, coherent search for
GRB-like signals, was run from +/-30 s around the neutrino candidate
time. The most significant result from this search was found T0+12 s
on the longest timescale of ~10 s and was best fit with the "normal"
spectral template described in arXiv:1612.02395. The GBM localization
is centered at RA, DEC = (123.8, 25.0) with a 90% credible region
spanning 10,084 square degrees. Modelling the neutrino localization
as a Gaussian with a width of 3 degrees and centered at the
coordinates reported by IceCube, we find the spatial consistency
between the localizations to be 1.8%. We therefore consider this
signal likely unrelated to IceCube-190629A.
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: 7.6e-07 8.6e-07 1.5e-06
1.024 s: 1.4e-07 2.7e-07 6.1e-07
8.192 s: 6.8e-08 1.3e-07 2.6e-07