Synchrotron emission in a random magnetic field: the effect of spectral ageing on radio images

By P. C. Tribble

Abstract

Images of radio synchrotron emission from volumes containing a random magnetic field have been constructed. The evolution of the images as the emission ages depends on the relative importance of synchrotron losses, inverse Compton losses, and diffusion of electrons between regions of different field strength. The polarization from the volume can vary substantially with frequency as the result of differential ageing of polarized components, although this will not be important for sheared field configurations. Synchrotron ageing naturally increases the emission contrast at high frequencies, so that instabilities need not be invoked to explain the brightness of filamentary structures.

Key words: magnetic fields -- radio continuum: galaxies -- radiation mechanisms: cyclotron and synchrotron

Contents:

Introduction
Model details
Images
Spectra
Polarization
Filamentary structures and instabilities
Conclusions
Acknowledgments
References

Also some notes on presentation


This article appeared in Monthly Notices of the Royal Astronomical Society, vol 269, pp. 110-120 (1994). Copyright Royal Astronomical Society.
Peter Tribble, peter.tribble@gmail.com