2024/11/16 by M. G. Dainotti, S. B. Bhardwaj, Dainotti, M. G. +9 · 1 citation
Environmental Science · #FOS: Physical sciences #High Energy Astrophysical Phenomena (astro-ph.HE) #Methane Hydrates and Related Phenomena
paper · pdf · doi:10.48550/arxiv.2411.10736
openalex publication_date 2024/11/16 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
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. In gamma-rays, we only explored the ν> max\νc,νm\ (SC/FC) cooling condition (where νc and νm are the cooling and characteristic frequencies, namely the frequencies at the spectral break). In the X-ray and optical bands, we explored all the cooling conditions, including νm < ν< νc (SC), νc < ν< νm (FC), and SC/FC, and found a clear preference for SC for X-rays and SC/FC for optical. Within these cooling conditions, X-rays exhibit the highest rate of occurrence for the density profile with k = 0, while the optical band has the highest occurrence for k = 2.5 when considering no energy injection. Although we can pinpoint a definite environment for some GRBs, we find degeneracies in other GRBs.