Prospects for >30 GeV observation of GRBs with HAWC Scalers

摘要

HAWC is a very high energy gamma ray observatory currently under construction in Mexico at 4100 m of altitude. Besides operating as an air shower array, HAWC will also include a scaler system that will be sensitive astrophysical gamma ray transients, specially GRBs. HAWC is the successor of Milagro and because of the increased altitude, size and improved detector design, the sensitivity of HAWC will be approx=15 times higher than Milagro's. We will show that HAWC scalers are sensitive enough to detect bursts similar to GRB 090510 and GRB 090902B. The prospect for positive detection of GRBs at E>30 GeV is very high given that HAWC's field of view will be approx=1/2 that of Fermi LAT. Operating by itself or jointly with the air shower mode of HAWC, the scaler system will be able to provide information about the high energy spectra of GRBs. Knowledge about the high-energy spectra of GRBs will lead to understanding e-pair attenuation in the GRB jets, extra-galactic background light absorption (EBL), as well as establishing the highest energy to which GRBs can accelerate particles.