Dependence of Temporal Properties on Energy in Long-Lag, Wide-Pulse Gamma-Ray Bursts

TL;DR

This study investigates how the temporal properties of long-lag, wide-pulse gamma-ray bursts depend on energy, revealing power-law relationships and correlations that suggest combined hydrodynamic and curvature effects influence observed pulse characteristics.

Contribution

It is the first to systematically analyze the energy dependence of multiple pulse temporal properties in long-lag, wide-pulse gamma-ray bursts, highlighting their power-law relationships and correlations.

Findings

Pulse peak time, rise time, and decay time scale follow power-law functions of energy.

Power-law indexes for pulse width, rise time, and decay time are correlated.

Pulse peak lag correlates strongly with CCF lag, less so with centroid lag.

Abstract

We employed a sample compiled by Norris et al. (2005, ApJ, 625, 324) to study the dependence of the pulse temporal properties on energy in long-lag, wide-pulse gamma-ray bursts. Our analysis shows that the pulse peak time, rise time scale and decay time scale are power law functions of energy, which is a preliminary report on the relationships between the three quantities and energy. The power law indexes associated with the pulse width, rise time scale and decay time scale are correlated and the correlation between the indexes associated with the pulse width and the decay time scale is more obvious. In addition, we have found that the pulse peak lag is strongly correlated with the CCF lag, but the centroid lag is less correlated with the peak lag and CCF lag. Based on these results and some previous investigations, we tend to believe that all energy-dependent pulse temporal properties may come from the joint contribution of both the hydrodynamic processes of the outflows and the curvature effect, where the energy-dependent spectral lag may be mainly dominated by the dynamic process and the energy-dependent pulse width may be mainly determined by the curvature effect.