Unification of Pulses in Long and Short Gamma-Ray Bursts: Evidence from Pulse Properties and their Correlations

Understand

We demonstrate that distinguishable gamma-ray burst pulses exhibit similar behaviors as evidenced by correlations among the observable pulse properties of duration, peak luminosity, fluence, spectral hardness, energy-dependent lag, and asymmetry.

• Long and Short burst pulses exhibit these behaviors, suggesting that a similar process is responsible for producing all GRB pulses.
• That these properties correlate in the observer's frame indicates that intrinsic correlations are strong enough to not be diluted into insignificance by the dispersion in distances and redshift.
• We show how all correlated pulse characteristics can be explained by hard-to-soft pulse evolution, and we demonstrate that "intensity tracking" pulses not having these properties are not single pulses; they instead appear to be composed of two or more overlapping hard-to-soft pulses.