Temporal properties of Swift GRBs with known redshifts

The Swift Gamma Ray Burst (GRB) mission has enabled the rapid detection of GRBs and the determination of the redshift of a greater proportion of source counterparts than previous missions. The mean redshift of the Swift GRBs is significantly higher than that of earlier missions. We present the results of a temporal analysis performed on 134 Swift long GRBs with known redshift. ‡ The GRBs were denoised using wavelets and subjected to an automatic pulse selection algorithm with the objective of identifying pulses. The rise times, fall times, full-width at half-maxima (FWHM), pulse amplitudes and pulse areas were measured and the frequency distributions of some of them are presented here. The results provide a comprehensive description of the pulse profiles in Swift GRBs with known redshift, determining that the temporal properties are consistent with lognormal distributions and that correcting for the known redshift of the source does not have a significant impact on the distributions. Lognormal distributions arise from random multiplicative processes and abound in a variety of natural phenomena.