Open AccessNo universality for the electron power‐law index ( p ) in gamma‐ray bursts and other relativistic sources
Author(s) -
Shen Rongfeng,
Kumar Pawan,
Robinson Edward L.
Publication year - 2006
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2006.10768.x
Subject(s) - physics , gamma ray burst , astrophysics , blazar , spectral index , power law , electron , pulsar , particle acceleration , distribution function , universality (dynamical systems) , spectral energy distribution , relativistic particle , gamma ray , astronomy , quantum mechanics , spectral line , galaxy , statistics , mathematics
The gamma‐ray burst (GRB) prompt emission is believed to be from highly relativistic electrons accelerated in relativistic shocks. From the GRB high‐energy power‐law spectral indices β observed by the Burst and Transient Source Experiment (BATSE) Large Area Detectors (LAD), we determine the spectral index, p , of the electrons' energy distribution. Both the theoretical calculations and numerical simulations of the particle acceleration in relativistic shocks show that p has a universal value ≈2.2–2.3. We show that the observed distribution of p during GRBs is not consistent with a δ‐function distribution or a universal p value, with the width of the distribution ≥0.54. The distributions of p during X‐ray afterglows are also investigated and found to be inconsistent with a δ‐function distribution. The p distributions in blazars and pulsar wind nebulae are also broad, inconsistent with a δ‐function distribution.