The normalization of the PVO log N-log P distribution

Abstract

The long duration of the Pioneer Venus Orbitor (PVO) mission has provided coverage of the infrequent, intense Gamma‐Ray Bursts (GRB) that occupy the −3/2 power law region of the log N‐log P distribution. The combination of the PVO events with the BATSE results on weaker events could provide the frequency distribution of GRBs over a range of 104 in intensity. Earlier work combined the BATSE and PVO results and concluded that they are not consistent with simple (i.e., no evolution) cosmological models involving standard candles. However, to utilize both databases, careful attention must be paid to the normalization of each data set. This paper presents a new renormalization of the PVO log N‐log P distribution which, when compared with the BATSE results, reduces the disagreement with the simple cosmological models from a greater than 3σ result to one between 2 and 3σ.