Search for TeV transients from Coalescing Binary systems discovered in Gravity Waves by LIGO/Virgo.

Abstract

The High Altitude Water Cherenkov (HAWC) Observatory is a wide-field continuously operating gamma-ray telescope. The detector consists of an array of 300 water tanks, each containing 200kTons of purified water instrumented with 4 larger area PMTs. The observatory is located at an elevation of 4100m a.s.l. near the Sierra Negra volcano in central Mexico. The combination of density, area and sensitivity gives HAWC an unprecedented threshold for air shower arrays, below 1 TeV. Unlike IACTs, the HAWC operates continuously (90% uptime) and can observe the entire overhead sky ( 2 sr), making it well suited for catching rapid transients from unknown directions and times. The LIGO/Virgo collaboration has recently discovered gravity wave ?bursts? emitted from coalescing massive compact objects. Gravity-wave detectors have very poor position resolution, making follow-up observations by narrow-field telescopes challenging. We have developed a systematic method for searching the locations where the probability contours overlap the HAWC field of view for gamma-ray transients. We describe in detail our analysis procedure and will report on our follow-ups observations of LIGO/Virgo triggers for both observation runs O1 and O2 (on going at the time of abstract submission).