Comparison of the Gamma‐Ray Burst Sensitivity of Different Detectors

Gamma-ray burst detectors are sensitive at different energies, complicating the comparison of the burst populations that they detect. Instrument teams often report their detector sensitivities in their instruments' energy band. I propose that sensitivities be reported as the threshold peak photon flux F T over the 1-1000 keV energy band for a specific spectral shape. The primary spectral parameter is E p , the energy of the maximum E 2 N ( E ) ∝ ν f ν . Thus, F T versus E p is a useful description of a detector's sensitivity. I find that Swift will be marginally more sensitive than BATSE for E p > 100 keV but significantly more sensitive for E p < 100 keV. Because of its low energy sensitivity, the FREGATE on HETE-2 is surprisingly sensitive below E p = 100 keV. Both the WFC on BeppoSAX and the WXM on HETE-2 are/were sensitive for low E p . As expected, the GBM on GLAST will be less sensitive than BATSE, while EXIST will be significantly more sensitive than Swift . The BeppoSAX GRBM was less sensitive that the WFC, particularly at low E p .