Comparison of the properties of short and long gamma-ray bursts observed with Phebus

The observation of subclasses within the classical Gamma-Ray Burst population is the first clue that the bursts may be produced by a small number of distinct mechanisms, sources, or initial conditions. Events in one subclass are characterized by a short duration (less than 2 seconds) and, on average, harder spectra compared to longer bursts. Here, we present a statistical study of GRB properties as observed with the PHEBUS experiment such as intensity, duration, spectral hardness, and the shape of their time profiles. We show which burst characteristics are common to both the long and short populations and which are not. Finally, we compare our results with BATSE observations. Specifically, we discuss the possible causes for the striking difference observed in the hardness-duration diagrams for the two experiments.