TITLE:   GCN CIRCULAR
NUMBER:  20707
SUBJECT: LIGO/Virgo G274296: Fermi-LAT search for a high-energy gamma-ray counterpart
DATE:    17/02/19 21:37:18 GMT
FROM:    Nicola Omodei at Stanford U  <nicola.omodei@stanford.edu>

Nicola Omodei (Stanford), Giacomo Vianello (Stanford),  Daniel Kocevski 
(NASA/MSFC) and Sara Buson (GSFC) report on behalf of the Fermi-LAT team:

We have searched data collected by the Fermi Large Area Telescope (LAT) 
for possible high-energy (E > 100 MeV) gamma-ray emission in 
spatial/temporal coincidence with the LIGO/Virgo trigger G274296.
The region of the LIGO map with probability >90% entered the LAT field 
of view at T0+400 (T0 = 2017-02-17 06:05:53 UTC), and reached full 
coverage at about 7ks from T0.
We searched for a transient counterpart within the LIGO 90% probability 
contour in the time window from T0  to T0 + 10 ks and found no 
significant new sources.
We also performed a search that adapted the time interval of the 
analysis to the exposure of each region of the sky. No significant 
candidate counterpart was found.

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.