LIGO/Virgo S200219ac: No counterpart candidates in Fermi-LAT observations
Abstract
We have searched data collected by the Fermi Large Area Telescope (LAT) on February 19, 2020, for possible high-energy (E > 100 MeV) gamma-ray emission in spatial/temporal coincidence with the LIGO/Virgo trigger S200219ac (GCN 27130). 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 no coverage at the time of the trigger (T0 = 2020-02-19 09:44:15.195 UTC), and reached 87% cumulative coverage after ~2.5 ks. The remaining region was not observed within 10 ks following the trigger time of the event. 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 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 1.4e-10 and 7.8e-08 [erg/cm^2/s]. The Fermi-LAT point of contact for this event is Feraol Dirirsa (fdirirsa@uj.ac.za). 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. ________________________________ This email and all contents are subject to the following disclaimer: http://disclaimer.uj.ac.za
- Publication:
-
GRB Coordinates Network
- Pub Date:
- February 2020
- Bibcode:
- 2020GCN.27143....1D