Speaker
Dirk Lennarz
(Georgia Tech)
Description
The temporal evolution and end of GRB spectra have important implications for the acceleration mechanisms of gamma-ray bursts (GRBs). Above $\approx10$ GeV the effective area of \emph{Fermi}-LAT is approximately constant and since the photon flux is steeply decreasing with energy, an insufficient number of photons is detected. The High Altitude Water Cherenkov (HAWC) observatory is a gamma-ray detector in the 100 GeV - 100 TeV range currently under construction in central Mexico that has the potential to measure GRB spectra beyond the LAT energy range. Unlike Imaging Atmospheric Cherenkov Telescopes, it has a large field of view and near 100 % duty cycle that will allow for observations of the prompt GRB phase. In this presentation I will show first results of GRB observations with the partially completed HAWC array, including GRB 130427A, the most energetic GRB so far detected at a redshift $z<0.5$.
Author
Dirk Lennarz
(Georgia Tech)
Co-author
HAWC collaboration for the
(HAWC collaboration)
