Optical inverse-Compton emission from clusters of galaxies

TL;DR

This paper models optical inverse-Compton emission from galaxy clusters, showing it increases with redshift and mass, and could be detected by advanced telescopes like Dragonfly.

Contribution

It provides an analytical calculation of optical IC emission from galaxy clusters, including energy loss effects, and predicts its detectability with new instruments.

Findings

Surface brightness increases with redshift and mass.

Potential detectability of IC emission by Dragonfly Telescope.

Surface brightness estimated at 32-34 mag arcsec$^{-2}$ for massive clusters.

Abstract

Shocks around clusters of galaxies accelerate electrons which upscatter the Cosmic Microwave Background photons to higher-energies. We use an analytical model to calculate this inverse Compton (IC) emission, taking into account the effects of additional energy losses via synchrotron and Coulomb scattering. We find that the surface brightness of the optical IC emission increases with redshift and halo mass. The IC emission surface brightness, 32--34~mag~arcsec$^{-2}$, for massive clusters is potentially detectable by the newly developed Dragonfly Telephoto Array.