Color diagrams of gamma‐ray bursts

We compute color‐color and color‐brightness diagrams for BATSE gamma‐ray bursts using peak fluxes and fluences. We describe some of the difficulties associated with color‐color diagrams due to systematic effects of data acquisition and interpretation. We find that faint bursts generally have a softer hardness ratio in the BATSE LAD middle energy channels, which cover the range from 50–300 keV. Although this may be consistent with a cosmological population of bursts, potential systematic effects prevent us from being definitive at this point. Our diagrams also indicate that there is a great deal of diversity of observed spectra of bursts and confirm that bursts cannot be explained by a universal power law.