White Dwarf Pulsars as Possible Gamma-Ray Sources

Abstract

The newly discovered white dwarf binary system AR Scorpii (AR Sco) with its fascinating nonthermal dominated multi-frequency emission has sparked renewed interest in potential high energy gamma-ray emission from white dwarf pulsars. Recent studies revealed that the optical and X-ray components of the emission in AR Sco can be powered entirely by the spin-down luminosity of the white dwarf in the absence of any mass accretion in this system. The Spectral Energy Distribution (SED) below and above optical shows a clear indication of a non-thermal synchrotron component, with pulsed emission in optical and X-ray bands at the white dwarf spin period as well as a beat with the binary period. From an energy perspective the highly magnetic rotating white dwarf can accelerate particles to TeV energies. In this study, a search for high energy gamma-