Duration and hardness ratio of Swift GRBs

TL;DR

This paper analyzes the duration and hardness ratio of Swift GRBs, revealing a separation at 0.65 seconds in rest-frame duration and examining the variability of hardness ratios across energy channels.

Contribution

It provides a detailed review of GRB durations and hardness ratios in the rest frame, highlighting a new classification boundary at 0.65 seconds.

Findings

Separation between two GRB classes at 0.65 s in rest frame.

Hardness ratio differences are less pronounced and depend on energy channels.

Distribution of GRB durations shows a clear bimodal pattern.

Abstract

We review the T_90 duration and hardness ratio of Swift Gamma Ray Bursts (GRBs). We focus on GRBs with known redshift and review their gamma properties in the GRBs rest frames. We find that GRBs number vs. T_90/(1+z) distribution shows a separation between two classes at 0.65 s. Furthermore, we find that the difference in hardness ratio between short and long bursts is not very pronounced and depends on energy channels used for comparison.