Electron Re-acceleration via Ion Cyclotron Waves in the Intracluster Medium

Understand

In galaxy clusters, the intracluster medium (ICM) is expected to host a diffuse, long-lived, and invisible population of "fossil" cosmic-ray electrons (CRe) with 1-100 MeV energies.

• These CRe, if re-accelerated by 100x in energy, can contribute synchrotron luminosity to cluster radio halos, relics, and phoenices.
• Re-acceleration may be aided by CRe scattering upon the ion-Larmor-scale waves that spawn when ICM is compressed, dilated, or sheared.
• We study CRe scattering and energy gain due to ion cyclotron (IC) waves generated by continuously-driven compression in 1D fully kinetic particle-in-cell simulations.