Gaussian-mixture-model-based cluster analysis of gamma-ray bursts in the
  BATSE catalog
  Clustering is an important tool to describe gamma-ray bursts (GRBs). We
analyzed the Final BATSE Catalog using Gaussian-mixture-models-based clustering
methods for six variables (durations, peak flux, total fluence and spectral
hardness ratios) that contain information on clustering. Our analysis found
that the five kinds of GRBs previously found by other authors are only the cut
groups of the previously well-known three types (short, long and intermediate
in duration). The two short and intermediate duration groups differ mostly in
the peak flux. Therefore, the reanalysis of the BATSE data finds similar group
structures than previously. Because the brightness distribution is asymmetric
and not correlated with durations or hardnesses the Gaussian mixture model cuts
the Short and the Intermediate duration groups into two subgroups, the dim ones
and the bright ones.
