GCN Circular 25841
Subject
LIGO/Virgo S190924h: Upper limits from Fermi-GBM Observations
Date
2019-09-24T12:05:42Z (6 years ago)
From
Eric Burns at GSFC <erickayserburns@gmail.com>
E. Burns (NASA/GSFC) reports on behalf of the Fermi-GBM Team and the
GBM-LIGO/Virgo group
For S190924h and using the initial bayestar skymap, Fermi-GBM was observing
100% of the localization probability at event time.
There was no Fermi-GBM onboard trigger around the event time of the
LIGO/Virgo detection of GW trigger S190924h (GCN 25829). 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.
We set upper limits on impulsive gamma-ray emission for the LVC
localization region. 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: 5.9 8.9 15.
1.024 s: 1.6 3.0 5.4
8.192 s: 0.3 0.6 1.1
Assuming the median luminosity distance of 514 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
------------------------------------
0.128 s: 2.7 3.8 11.
1.024 s: 0.7 1.3 3.8
8.192 s: 0.1 0.3 1.1