The Optical and Ultraviolet Spectral Energy Distributions of Short‐Period Black Hole X‐Ray Transients in Outburst

Abstract

We compile optical and UV spectra of a sample of ``typical'' short-period black hole X-ray transients in outburst. We also survey determinations of interstellar extinction and distance to deredden spectra and compare absolute fluxes. Hence, we perform a comparative study of the broadband spectral energy distributions (SEDs). We find that, given such a homogeneous sample of typical sources, the optical SEDs form a relatively uniform set, all exhibiting quasi-power-law spectra with Fν~να, where 0.5