EXTRAPOLATIONS OF BATSE GAMMA-RAY BURST SPECTRA TO THE OPTICAL-ULTRAVIOLET BAND

Many gamma-ray burst counterpart searches are being conducted in the o ptical-UV band. To both predict detectability and understand the meani ng of any detections or upper limits, we extrapolate gamma-ray spectra from 54 bright gamma-ray bursts to optical-UV energies. We assume opt ical emission is concurrent with gamma-ray emission and do not conside r quiescent or fading counterparts. We find that the spectrum must be steeper (greater flux at low energy) than a simple extrapolation of th e gamma-ray spectrum for more than one simultaneous optical flash to b e observable per year by current searches.