Jitter radiation images, spectra, and light curves from a relativistic spherical blastwave

TL;DR

This paper investigates jitter radiation from a relativistic blastwave, comparing its images, spectra, and light curves to synchrotron radiation, and discusses how these differences could help distinguish the emission mechanisms in astrophysical observations.

Contribution

The study provides the first detailed calculations of jitter radiation images, spectra, and light curves from a relativistic blastwave, contrasting them with synchrotron results.

Findings

Jitter radiation spectra are slightly flatter than synchrotron spectra between self-absorption and peak frequencies.

Jitter and synchrotron afterglows can be distinguished with high-quality observations.

Differences in jitter and synchrotron spectra are unlikely to explain some peculiar observational behaviors.

Abstract

We consider radiation emitted by the jitter mechanism in a Blandford-McKee self-similar blastwave. We assume the magnetic field configuration throughout the whole blastwave meets the condition for the emission of jitter radiation and we compute the ensuing images, light curves and spectra. The calculations are performed for both a uniform and a wind environment. We compare our jitter results to synchrotron results. We show that jitter radiation produces slightly different spectra than synchrotron, in particular between the self-absorption and the peak frequency, where the jitter spectrum is flat, while the synchrotron spectrum grows as \nu^{1/3}. The spectral difference is reflected in the early decay slope of the light curves. We conclude that jitter and synchrotron afterglows can be distinguished from each other with good quality observations. However, it is unlikely that the difference can explain the peculiar behavior of several recent observations, such as flat X-ray slopes and uncorrelated optical and X-ray behavior.