Inverse-Compton emission from halos around stars

TL;DR

This paper examines how the clumpy distribution of stellar radiation fields affects inverse Compton emission in the Galaxy, highlighting the potential observability of luminous stars with GLAST.

Contribution

It introduces a model accounting for the clumpy ISRF due to luminous stars, updating previous work on inverse Compton emission predictions.

Findings

Clumpy ISRF significantly influences inverse Compton emission distribution.

Some luminous stars may be detectable by GLAST.

Updated spectrum predictions for Cygnus OB2.

Abstract

Inverse Compton scattering by relativistic electrons produces a major component of the diffuse emission from the Galaxy. The photon fields involved are the cosmic microwave background and the interstellar radiation field from stars and dust. Calculations of the inverse Compton distribution have usually assumed a smooth ISRF, but in fact a large part of the Galactic luminosity comes from the most luminous stars which are rare. Therefore we expect the ISRF, and hence the inverse Compton emission, to be clumpy. We also show that some of the most luminous stars may be visible to GLAST. In this paper we give an update on our previous work including examples of the intensity distribution around stars, and the predicted spectrum of Cygnus OB2.