GCN Circular 26224
Subject
LIGO/Virgo S191110af: Upper limits from Fermi-GBM Observations
Date
2019-11-11T04:57:15Z (5 years ago)
From
Colleen A. Wilson at NASA/MSFC/NSSTC <colleen.wilson@nasa.gov>
C.A. Wilson-Hodge (NASA/MSFC) reports on behalf of the Fermi-GBM Team and the GBM-LIGO/Virgo group
For S191110af and using the initial cWB.fits.gz skymap, Fermi-GBM was observing 90.5% 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 S191110af (GCN 26222). 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=315.2, Dec=9.0 with a radius of 67.5 degrees. We therefore set upper limits on impulsive gamma-ray emission for the LVC localization region visible to Fermi 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 norm hard
--------------------------------------
0.128 s: 7.4 12. 20.
1.024 s: 2.2 3.4 5.6
8.192 s: 0.8 1.1 2.3