Search

The Short GAmma Ray Front Air-Cherenkov Experiment (SGARFACE) uses the Whipple 10 m telescope to search for bursts of gamma rays. Bursts can be detected on time scales from a few ns to 20 !s and with gamma-ray energy above 100 MeV. SGARFACE began operating in March 2003 and has acquired 2.2 million events since. A search for explosions of primordial black holes (PBH) was carried out using the recorded time-resolved images. No unambiguous burst detection could be made due to background events produced by cosmic rays. Upper limits on the PBH explosion rare are presented and compared to other experiments. [ABSTRACT FROM AUTHOR]

This is a short report on the preliminary findings of the gamma ray burst (GRB) working group for the white paper on the status and future of very high energy (VHE;>50 GeV) gamma-ray astronomy. The white paper discusses the status of past and current attempts to observe GRBs at GeV-TeV energies, including a handful of low-significance, possible detections. The white paper concentrates on the potential of future ground-based gamma-ray experiments to observe the highest energy emission ever recorded for GRBs, particularly for those that are nearby and have high Lorentz factors in the GRB jet. It is clear that the detection of VHE emission would have strong implications for GRB models, as well as cosmic ray origin. In particular, the extended emission phase (including both afterglow emission and possible flaring) of nearby long GRBs could provide the best possibility for detection. The difficult-to-obtain observations during the prompt phase of nearby long GRBs and short GRBs could also provide particularly strong constraints on the opacity and bulk Lorentz factors surrounding the acceleration site. The synergy with upcoming and existing observatories will, of course, be critical for both identification of GRBs and for multiwavelength/multimessenger studies. [ABSTRACT FROM AUTHOR]