[vsnet-grb-info 24130] LIGO/Virgo S191110af: No counterpart candidates in Fermi-LAT observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  26229
SUBJECT: LIGO/Virgo S191110af: No counterpart candidates in Fermi-LAT observations
DATE:    19/11/11 11:44:37 GMT
FROM:    Makoto Arimoto at Tokyo Inst of Tech  <arimoto at hp.phys.titech.ac.jp>

M. Arimoto (Kanazawa Univ.), M. Moss (GWU), S. Cutini (INFN Perugia),
D. Kocevski (NASA/MSFC), N. Omodei (Stanford Univ.), M. Axelsson (KTH
and Stockholm Univ.),
E. Bissaldi (Politecnico and INFN Bari) and F. Longo (Univ. and INFN Trieste)
report on behalf of the Fermi-LAT Collaboration:


We have searched data collected by the Fermi Large Area Telescope (LAT)
on Nov 10, 2019, for possible high-energy (E > 100 MeV) gamma-ray emission
in spatial/temporal coincidence with the LIGO/Virgo trigger S191110af
(GCN 26222).

We define "instantaneous coverage" as the integral over the region
of the LIGO probability map that is within the LAT field of view at a
given time,
and "cumulative coverage" as the integral of the instantaneous
coverage over time.
Fermi-LAT had an instantaneous coverage of ~18% of the LIGO probability region
at the time of the trigger (T0 = 2019-11-10 23:06:44.183 UTC)
and reached 100% cumulative coverage at approximately T0 + 5 ks.

We performed a search for a transient counterpart within the observed region
of the 90% contour of the LIGO map in a fixed time window from T0 to T0 + 10 ks.
No significant sources were found.

We also performed a search which adapted the time interval of the analysis
to the exposure of each region of the sky, and no additional excesses
were found.

Energy flux upper bounds between 100 MeV and 1 GeV
for the fixed time interval of this search vary
between 2.3e-10 and 1.3e-7 [erg/cm^2/s].

The Fermi-LAT point of contact for this event
is Michael Moss (michaelmoss at gwmail.gwu.edu).

The Fermi-LAT is a pair conversion telescope designed to cover
the energy band from 20 MeV to greater than 300 GeV.
It is the product of an international collaboration between
NASA and DOE in the U.S. and many scientific institutions
across France, Italy, Japan and Sweden.