GCN Circular 21448

I. Martinez-Castellanos (University of Maryland, College Park) and
A.J. Smith (University of Maryland, College Park) on behalf of the
HAWC Collaboration:

HAWC performed a follow-up of LIGO trigger G296853. At the time
of the trigger only a small portion (6%) of the probability distribution
overlapped with HAWC field of view (FOV), and it was located at a
large zenith angle where the sensitivity is poorest. The real-time
search was preformed and identified no candidate counterparts.

Additionally we searched for longer duration emission integrating the
next transit of the LIGO contour through HAWC's FOV. The most
probable location transited 1-3hrs after the trigger (~41deg from
zenith at culmination). In total, 52% of the LIGO probability contour
was observed. There were no significant detections (5-sigma).

HAWC is a TeV gamma ray water Cherenkov array located in the
state of Puebla, Mexico. It is sensitive to the energy range
~0.5-100TeV, and monitors 2/3 of the sky every day with an
instantaneous field-of-view of ~2 sr.