Global characteristics of X-ray flashes and X-ray rich GRBs observed by HETE-2

摘要

We describe and discuss the global properties of 45 gamma-ray bursts (GRBs) observed by HETE-2 during the first three years of its mission, forcing on the properties of X-Ray Flashes (XRFs) and X-ray-rich GRBs (XRRs). We find that: 1) the numbers of XRFs, XRRs, and GRBs are comparable, 2) the durations of XRFs and XRRs are similar to those of GRBs, and 3) the spectral properties of XRFs and XRRs are similar to those of GRBs, expect that the values of the peak energy E peak of the burst spectrum is νF ν, the peak flux F, and the fluence S of XRFs are much smaller --and those of XRRs are smaller-- than those of GRBs. These results provide strong evidence that all three kinds of bursts arise from the same phenomenon.-1