Closure Relations of Synchrotron Self-Compton in Afterglow stratified medium and Fermi-LAT Detected Gamma-Ray Bursts

Abstract

The Second Gamma-ray Burst Catalog (2FLGC) was announced by the Fermi Large Area Telescope (Fermi-LAT) Collaboration. It includes 29 bursts with photon energy higher than 10 GeV. Gamma-ray burst (GRB) afterglow observations have been adequately explained by the classic synchrotron forward-shock model, however, photon energies greater than 10 GeV from these transient events are challenging, if not impossible, to characterize using this afterglow model. Recently, the closure relations (CRs) of the synchrotron self-Compton (SSC) forward-shock model evolving in a stellar wind and homogeneous medium was presented to analyze the evolution of the spectral and temporal indexes of those bursts reported in 2FLGC. In this work, we provide the CRs of the same afterglow model, but evolving in an intermediate density profile ($\propto {\mathrm{r}}^{-\mathrm{k}}$) with $0\le \mathrm{k}\le 2.5$, taking into account the adiabatic/radiative regime and with/without energy injection for any value of the electron spectral index. The results show that the current model accounts for a considerable subset of GRBs that cannot be interpreted in either stellar-wind or homogeneous afterglow SSC model. The analysis indicates that the best-stratified scenario is most consistent with $\mathrm{k}=0.5$ for no-energy injection and $\mathrm{k}=2.5$ for energy injection.

13 pages, 3 figures

References in corpus (16)

• The Physics of Gamma-Ray Bursts and Relativistic Jets
• X-Ray Flares from Postmerger Millisecond Pulsars
• The First Survey of X-ray Flares from Gamma Ray Bursts Observed by Swift: Temporal Properties and Morphology
• A decade of Gamma-Ray Bursts observed by $Fermi$-LAT: The 2${}^{nd}$ GRB catalog
• Klein-Nishina Effects on Optically Thin Synchrotron and Synchrotron Self-Compton Spectrum
• Search for Prompt Neutrino Emission from Gamma-Ray Bursts with IceCube
• Properties of Gamma-Ray Burst Progenitor Stars
• Multiwavelength observations of GRB 110731A: GeV emission from onset to afterglow
• On the Existence of the Plateau Emission in High-Energy Gamma-Ray Burst LightCurves observed byFermi-LAT
• Closure relations during the plateau emission of Swift GRBs and the fundamental plane
• Modeling the high-energy emission in GRB 110721A and implications on the early multiwavelength and polarimetric observations
• Astrophysics: Extreme emission seen from $\gamma$-ray bursts
• Closure relations of Gamma Ray Bursts in high energy emission
• Flares in Gamma Ray Bursts: Disc Fragmentation and Evolution
• GeV Emission from Prompt and Afterglow Phases of Gamma-Ray Bursts
• Late Central Engine Activity in GRB 180205A