Constraints on Electron Acceleration in Gamma-Ray Bursts Afterglows from Radio Peaks

Abstract

Studies of gamma-ray bursts (GRBs) and their multi-wavelength afterglows have led to insights in electron acceleration and emission properties from relativistic, high-energy astrophysical sources. Broadband modeling across the electromagnetic spectrum has been the primary means of investigating the physics behind these sources, although independent diagnostic tools have been developed to inform and corroborate assumptions made in particle acceleration simulations and broadband studies. We present a methodology to constrain three physical parameters related to electron acceleration in GRB blast waves: the fraction of shock energy in electrons, ${\epsilon }_e$; the fraction of electrons that gets accelerated into a power-law distribution of energies, ${\xi }_e$; and the minimum Lorentz factor of the accelerated electrons, ${\gamma }_m$. These parameters are constrained by observations of the peaks in radio afterglow light curves and spectral energy distributions. From a sample of 49 radio afterglows, we are able to find narrow distributions for these parameters, hinting at possible universality of the blast wave microphysics, although observational bias could play a role in this. Using radio peaks and considerations related to the prompt gamma-ray emission efficiency, we constrain the allowed parameter ranges for both ${\epsilon }_e$ and ${\xi }_e$ to within about one order of magnitude, $0.01\lesssim {\epsilon }_e\lesssim 0.2$ and $0.1\lesssim {\xi }_e\lesssim 1$. Such stringent constraints are inaccessible for ${\xi }_e$ from broadband studies due to model degeneracies.

arXiv comment10 pages, 6 figures, 2 tables; accepted for publication in MNRAS

References in corpus (52)

• Spectra and Light Curves of Gamma-Ray Burst Afterglows
• Discovery of the X-Ray Afterglow of the Gamma-Ray Burst of February 28 1997
• The Shape of Spectral Breaks in GRB Afterglows
• Particle acceleration by ultra-relativistic shocks: theory and simulations
• On The Synchrotron Self-Compton Emission from Relativistic Shocks and Its Implications for Gamma-Ray Burst Afterglows
• Gamma-ray bursts from internal shocks in a relativistic wind: temporal and spectral properties
• Physical parameters of GRB 970508 and GRB 971214 from their afterglow synchrotron emission
• Particle Acceleration in Relativistic Magnetized Collisionless Electron-Ion Shocks
• Multi-Epoch VLBA Observations of EGRET-Detected Quasars and BL Lac Objects: Superluminal Motion of Gamma-Ray Bright Blazars
• Gamma-Ray Burst Environments and Progenitors
• Particle acceleration at ultrarelativistic shocks: an eigenfunction method
• The microphysics of collisionless shock waves
• A 450-day light curve of the radio afterglow of GRB 970508: Fireball calorimetry
• A Study of the Afterglows of Four GRBs: Constraining the Explosion and Fireball Model
• A Radio-Selected Sample of Gamma Ray Burst Afterglows
• Observation of inverse Compton emission from a long $\gamma$-ray burst
• The Afterglow of GRB 130427A from 1 to 10^16 GHz
• Afterglow Observations of Fermi-LAT Gamma-Ray Bursts and the Emerging Class of Hyper-Energetic Events
• Prompt high-energy emission from gamma-ray bursts in the internal shock model
• Gamma-ray burst afterglow broadband fitting based directly on hydrodynamics simulations
• Energies of GRB blast waves and prompt efficiencies as implied by modeling of X-ray and GeV afterglows
• The efficiency of electron acceleration in collisionless shocks and GRB energetics
• Gamma Ray Bursts Are Observed Off-Axis
• Opening angles, Lorentz factors and confinement of X-ray binary jets
• Particle acceleration in relativistic outflows
• Energy Injection in Gamma-ray Burst Afterglows
• Accurate Calorimetry of GRB 030329
• Electrons' energy in GRB afterglows implied by radio peaks
• Constraints on the Synchrotron Emission Mechanism in GRBs
• A Comprehensive Radio View of the Extremely Bright Gamma-Ray Burst 130427A
• Gamma-Ray Burst Afterglows as Probes of Environment and Blastwave Physics II: the Distribution of p and Structure of the Circumburst Medium
• Detailed study of the GRB 030329 radio afterglow deep into the non-relativistic phase
• A Reverse Shock in GRB 160509A
• GRB 091127: The cooling break race on magnetic fuel
• Clustering of LAT light curves: a clue to the origin of high-energy emission in Gamma-Ray Bursts
• Constraints on millisecond magnetars as the engines of prompt emission in gamma-ray bursts
• A Reverse Shock and Unusual Radio Properties in GRB 160625B
• First ALMA Light Curve Constrains Refreshed Reverse Shocks and Jet Magnetization in GRB 161219B
• Radio Afterglows of Very High Energy Gamma-Ray Bursts 190829A and 180720B
• Thermal Electrons in GRB Afterglows
• Synchrotron self-absorption in GRB afterglows: the effects of a thermal electron population
• The Arcminute Microkelvin Imager Catalogue of Gamma-ray Burst afterglows at 15.7 GHz
• Illuminating the Darkest Gamma-Ray Bursts with Radio Observations
• The radio afterglow of GRB 030329 at centimeter wavelengths: evidence for a structured jet or non-relativistic expansion
• Non-linear collisionless damping of Weibel turbulence in relativistic blast waves
• The luminous host galaxy, faint supernova and rapid afterglow rebrightening of GRB 100418A
• A VLA Study of High-redshift GRBs I - Multi-wavelength Observations and Modeling of GRB 140311A
• Happy Birthday Swift: Ultra-long GRB141121A and its broad-band Afterglow
• Radio observations of GRB 100418a: Test of an energy injection model explaining long-lasting GRB afterglows
• An Unexpectedly Small Emission Region Size Inferred from Strong High-Frequency Diffractive Scintillation in GRB 161219B
• Detailed Afterglow Modeling and Host Galaxy Properties of the Dark GRB 111215A
• Detailed multi-wavelength modelling of the dark GRB 140713A and its host galaxy

Cited by in corpus (4)

• Evidence for a compact stellar merger origin for GRB 230307A from Fermi-LAT and multi-wavelength afterglow observations
• The Signature of Refreshed Shocks in the of Afterglow of GRB030329
• Rapid radio brightening of GRB 210702A
• Discovery and Analysis of Afterglows from Poorly Localised GRBs with the Gravitational-wave Optical Transient Observer (GOTO) All-sky Survey