GCN Circular 24513

S. Poolakkil (UAH) and C.M. Hui (NASA/MSFC) report on behalf of the
Fermi-GBM Team
and the GBM-LIGO/Virgo group:

For S190512at, and using the updated BAYESTAR skymap, Fermi-GBM was
observing 34.7% 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 S190512at (GCN 24503
Not found
 
 
). 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 = 308.1 and Dec = -3.6 with a radius of 67.2 degrees.
We therefore set upper limits on impulsive gamma-ray emission.  Using the
representative soft, normal, and hard GRB-like spectral templates described
in arXiv:1612.02395
Not found
 
 
, we set the following 3 sigma flux upper limits over
10-1000 keV,
weighted by the remaining visible GW localization probability (in units of
erg/s/cm^2):

Timescale  soft       norm       hard
-----------------------------------------------
0.128 s:   2.4e-07  4.3e-07  1.0e-06
1.024 s:   5.3e-08  1.1e-07  2.5e-07
8.192 s:   2.3e-08  2.3e-08  8.0e-08

Assuming the median luminosity distance of ~1331 Mpc from the GW detection,
we
estimate intrinsic luminosity upper limits of (0.8-7.9)E49 erg/s for the
soft template, (0.7-12.7)E49 erg/s for the normal template, and
(3.9-49.3)E49 erg/s
for the hard template over the 1 keV-10 MeV energy range.