GRB Closure Relationship in Multi-wavelength
Speaker: Shubham Bhardwaj (D2, SOKENDAI/NAOJ)
Abstract:
Gamma-ray bursts (GRBs) are intense pulses of high-energy emission associated with massive stars’ death or compact objects’ coalescence. Their multi-wavelength observations help verify the reliability of the standard fireball model. We analyze 14 GRBs observed contemporaneously in gamma-rays by the Fermi Large Area Telescope (LAT), in X-rays by the Swift Telescope, and in the optical bands by Swift and many ground-based telescopes. We study the correlation between the spectral and temporal indices using closure relations according to the synchrotron forward-shock model in the stratified medium (n ∝r^{-k}) with k ranging from 0 to 2.5. We find that the model without energy injection is preferred over the one with energy injection in all the investigated wavelengths.