[vsnet-grb-info 22818] IceCube-190629A: Upper limits from Fermi-GBM Observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  24917
SUBJECT: IceCube-190629A: Upper limits from Fermi-GBM Observations
DATE:    19/06/30 13:27:38 GMT
FROM:    Rachel Hamburg at UAH  <rkh0007 at 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