Investigation of the spectral lag - energy relation of GRBs registered by INTEGRAL

TL;DR

This study examines how spectral lag varies with energy in 28 bright GRBs detected by INTEGRAL, revealing a logarithmic relation in simple bursts and linking lag to pulse duration.

Contribution

It introduces a logarithmic model for spectral lag dependence on energy and explores its correlation with pulse duration in GRBs.

Findings

Spectral lag follows a t=Alog(E) relation in simple bursts.

No negative lag observed in well-separated pulses.

Negative lag may occur due to spectral differences across pulses.

Abstract

We investigated the dependence of spectral lag on energy band based on 28 bright GRBs detected by the SPI and IBIS/ISGRI instruments on the INTEGRAL observatory. It is found that for simple structured bursts or well separated pulses of multi-pulse bursts the spectral lag can be approximated by the relation t=Alog(E), where A is a positive parameter, which correlates with pulse duration. We have not found any negative lag in simple structured bursts or in well separated pulses. While investigating the time profile of the whole burst negative lag may appear due to different spectral parameters of the pulses.