Synchrotron Self-Compton Afterglow Closure Relations and Fermi-LAT Detected Gamma-Ray Bursts

Abstract

The Fermi Large Area Telescope (Fermi-LAT) Collaboration reported the Second Gamma-ray Burst Catalog (2FLGC), which comprises a subset of 29 bursts with photon energies above 10 GeV. Although the standard synchrotron forward-shock model has successfully explained the Gamma-ray burst (GRB) afterglow observations, energetic photons higher than 10 GeV from these transient events can hardly be described in this scenario. We present the closure relations (CRs) of synchrotron self-Compton (SSC) afterglow model in the adiabatic and radiative scenario and when the central engine injects continuous energy into the blastwave to study the evolution of the spectral and temporal indexes of those bursts reported in 2FLGC. We consider the SSC afterglow model evolving in stellar-wind and interstellar medium, and the CRs as a function of the radiative parameter, the energy injection index, and the electron spectral index for $1<p<2$ and $2\le p$. We select all GRBs that have been modeled with both a simple or a broken power law in the 2FLGC. We found that the CRs of the SSC model can satisfy a significant fraction of burst that cannot be interpreted in the synchrotron scenario, even though those that require an intermediate density profile (e.g., GRB 130427A) or an atypical fraction of total energy given to amplify the magnetic field (${\epsilon }_B$). The value of this parameter in the SSC model ranges (${\epsilon }_B\approx 10^{-5}-10^{-4}$) when the cooling spectral break corresponds to the Fermi-LAT band for typical values of GRB afterglow. The analysis shows that ISM is preferred for the scenario without energy injection and the stellar wind medium for an energy injection scenario.

14 pages, 2 figures, accepted for publication in ApJ

References in corpus (20)

• 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
• Multiwavelength observations of GRB 110731A: GeV emission from onset to afterglow
• Analysis and modelling of the multi-wavelength observations of the luminous GRB 190114C
• On the investigation of the closure relations for Gamma-Ray Bursts observed by Swift in the post-plateau phase and the GRB fundamental plane
• On the origin of the multi-GeV photons from the closest burst with intermediate luminosity: GRB 190829A
• On the Existence of the Plateau Emission in High-Energy Gamma-Ray Burst LightCurves observed byFermi-LAT
• GRB Fermi-LAT afterglows: explaining flares, breaks, and energetic photons
• GRB 110731A: Early afterglow in stellar wind powered by a magnetized outflow
• Closure relations during the plateau emission of Swift GRBs and the fundamental plane
• Modeling the early afterglow in the short and hard GRB 090510
• Astrophysics: Extreme emission seen from $\gamma$-ray bursts
• Modeling the high-energy emission in GRB 110721A and implications on the early multiwavelength and polarimetric observations
• Flares in Gamma Ray Bursts: Disc Fragmentation and Evolution
• Closure relations of Gamma Ray Bursts in high energy emission
• Late Central Engine Activity in GRB 180205A

Cited by in corpus (5)

• The closure relations in optical afterglow of Gamma-Ray Bursts
• Closure Relations of Synchrotron Self-Compton in Afterglow stratified medium and Fermi-LAT Detected Gamma-Ray Bursts
• Probing gamma-ray bursts observed at very high energies through their afterglow
• Probing Gamma-Ray Burst afterglows with the Cherenkov Telescope Array
• Synchrotron self-Compton Reverse Shock in Energy-Injection and Radiative Scenarios