Paper detail

Standard Cosmology and the BATSE Number vs. Peak Flux Distribution

The observed 2B BATSE distribution is consistent with the faintest GRBs in our sample originating from a redshift of Zmax ~ 0.8-3.0 (90\%), with the most likely values in the range of 1.0-2.2, and is largely insensitive to Omega for models with no evolution. To constrain the model parameter Omega to the range 0.1-1.0 using only Log N -- Log P distributions, more than 4000 GRBs, with a most likely value of ~ 9,000 GRBs to BATSE sensitivity. This requires a live integration time of >6 years with BATSE. Detectors sensitive to much lower limits (~ 70-400 in sensitivity) require ~ 200 GRBs, with <0.03 year 4pi ster coverage. We place limits on the amount of frequency density and, separately, peak luminosity evolution in the sample of GRBs. We find that frequency density evolution models can place the faintest GRBs at Zmax ~ 10-200, without conflicting with the observations of relative time dilation of ~ 2.