[vsnet-grb-info 24646] LIGO/Virgo S200114f: No counterpart candidates in Fermi-LAT observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  26745
SUBJECT: LIGO/Virgo S200114f: No counterpart candidates in Fermi-LAT observations
DATE:    20/01/14 11:02:00 GMT
FROM:    Lorenzo Scotton at CNRS/IN2P3/LUPM  <lorenzoscotton at live.it>

L. Scotton (CNRS/IN2P3/LUPM), M. Crnogorcevic (Univ. of Maryland & 
NASA/GSFC), M. Axelsson (KTH & Stockholm Univ.) and F. Longo (University 
and INFN, Trieste) report on behalf of the Fermi-LAT Collaboration:

We have searched data collected by the Fermi Large Area Telescope (LAT) 
on Jan 14, 2020, for possible high-energy (E > 100 MeV) gamma-ray 
emission in spatial/temporal coincidence with the LIGO/Virgo trigger 
S200114f (GCN 26734).

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 ~87% of 
the LIGO probability at the time of the trigger (T0 = 
2020-01-1402:08:18.230UTC), and reached 100% cumulative coverage after 
~4.2 ks.

We performed a search for a transient counterpart within the observed 
region of the 90% contour of LIGO map in a fixed time window from T0 to 
T0 + 10 ks. No significant new sources are 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 for the fixed time interval between 100 MeV and 
1 GeV for this search vary between 2e-10 and 2e-08 [erg/cm^2/s].

The Fermi-LAT point of contact for this event is Milena Crnogorcevic 
(mcrnogor at astro.umd.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.