Selection Effects and the BATSE E-Peak Distribution

The characteristic spectral energy of a gamma-ray burst can be characterized by the energy at which the nu F_nu spectrum has a maximum. This is called the e-peak value (E_p). The distribution of E_p values for the BATSE gamma-ray bursts is narrow, with the medium value occurring at approx 250 keV, and half-maxima at approx 100 keV and 700 keV. An important question is the role instrumental effects play in creating this distribution. I show that instrumental effects alone cannot explain the observed distribution, and that the intrinsic distribution must be narrow. This limits gamma-ray burst theories to those that in some way tie the gamma-ray burst spectrum to the rest frame of the host galaxy.