4.3. Gamma-Ray Bursts

Although the -ray burst phenomenon is usually associated with energies of 100 keV-1 MeV (hard X-rays to low-energy -rays), results from EGRET show that there is a component at high energies, and thus the phenomenon has the potential to be observed in the TeV range. The power spectrum certainly peaks in the lower energy ranges, but the observations at high energies really provide the strongest constraints on the emission models and may ultimately expose the underlying emission mechanism. The detection of a single photon of energy 18 GeV from GRB 970217, 1.5 hours after the onset of the burst (Hurley et al. 1994), has opened the possibility of delayed emission of GeV-TeV photons (e.g., Totani 1998; Bottcher & Dermer 1998). Although ACITs have, to date, only presented upper limits (e.g., Connaughton et al. 1997), it is possible that in the near future wide field air shower detectors such as MILAGRO or the Tibet Air Shower Array might detect a prompt VHE emission component and rapid slew ACITs might do the same with greater sensitivity for any delayed emission.