- Conference date: 15–17 October 1992
- Location: St. Louis, MO, USA
We analyze the distribution of gamma‐ray burst peak count rates reported by BATSE in the context of a variety of isotropic phenomenological and physical models using Bayesian methods. These methods fit the differential count distribution, but do so without binning or averaging data (in contrast to, say, χ2 or 〈V/V max〉 analyses), and take known selection effects and biases into account. Using phenomenological broken power‐law models, we find significant evidence for steepening in the log R(≳Φ)‐log Φ distribution from R(≳Φ)∝Φ−1 below Φb≫4–40 cm−2 s−1, to R(≳Φ)∝Φ−3/2 above Φb. We then study three families of cosmological models: standard candle models, standard candle models with power‐law density evolution, and models with power‐law luminosity functions. We find that although the data require curvature in the log R(≳Φ)‐log Φ distribution, they are too sparse to distinguish among the cosmological alternatives.
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