GCN Circular 26205
Subject
LIGO/Virgo S191109d: Upper limits from Fermi-GBM Observations
Date
2019-11-09T05:51:52Z (5 years ago)
From
Peter Veres at UAH <veresp@gmail.com>
P. Veres (UAH) reports on behalf of the Fermi-GBM Team and the
GBM-LIGO/Virgo group:
For S191109d and using the initial BAYESTAR skymap, Fermi-GBM was observing
87.2% of the localization probability at event time.
There was no Fermi-GBM onboard trigger around the event time of S191109d
(GCN 26202). 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 merger
time, and also identified no counterpart candidates.
Part of the LVC localization region is behind the Earth for Fermi, located
at RA= 320.9, Dec= 12.1 with a radius of 67.5 degrees. We therefore set
upper limits on impulsive gamma-ray emission for the LVC localization
region visible to GBM at merger time. 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, weighted by GW
localization probability (in units of 10^-7 erg/s/cm^2):
Timescale soft normal hard
--------------------------------------
0.128 s: 6.3 9.5 23
1.024 s: 1.5 2.3 5.5
8.192 s: 0.50 0.76 1.4
Assuming the median luminosity distance of 1810 Mpc from the GW detection,
we estimate the following intrinsic luminosity upper limits over the 1
keV-10 MeV energy range (in units of 10^49 erg/s):
Timescale Soft Normal Hard
------------------------------------
0.128s: 38 52 210
1.024s: 9.2 13 50
8.192s: 3.1 4.1 13