Dots, clumps and filaments: the intermittent images of synchrotron emission in random magnetic fields of young supernova remnants

TL;DR

This paper investigates how random magnetic fields in young supernova remnants create intermittent, clumpy synchrotron X-ray images, revealing that magnetic field concentrations significantly enhance high-energy emission and produce structures similar to observations.

Contribution

It demonstrates that turbulent magnetic fields cause localized high-intensity structures in synchrotron images, explaining observed features in supernova remnants.

Findings

Magnetic field concentrations produce dots, clumps, and filaments in synchrotron images.

Intermittent structures can have short lifetimes consistent with observations.

Turbulent fields enhance synchrotron efficiency compared to uniform fields.

Abstract

Non-thermal X-ray emission in some supernova remnants originates from synchrotron radiation of ultra-relativistic particles in turbulent magnetic fields. We address the effect of a random magnetic field on synchrotron emission images and spectra. A random magnetic field is simulated to construct synchrotron emission maps of a source with a steady distribution of ultra-relativistic electrons. Non-steady localized structures (dots, clumps and filaments), in which the magnetic field reaches exceptionally high values, typically arise in the random field sample. These magnetic field concentrations dominate the synchrotron emission (integrated along the line of sight) from the highest energy electrons in the cut-off regime of the distribution, resulting in an evolving, intermittent, clumpy appearance. The simulated structures resemble those observed in X-ray images of some young supernova remnants. The lifetime of X-ray clumps can be short enough to be consistent with that observed even in the case of a steady particle distribution. The efficiency of synchrotron radiation from the cut-off regime in the electron spectrum is strongly enhanced in a turbulent field compared to emission from a uniform field of the same magnitude.