X-rays and γ-rays from cataclysmic variables: the example case of intermediate polar V1223 Sgr

• Published in: Monthly notices of the Royal Astronomical Society 2011-03, Vol.411 (3), p.1701-1706
• Main Authors: Bednarek, W., Pabich, J.
• Format: Article
• Language: English
• Subjects: binaries: close; gamma-rays: stars; radiation mechanisms: non-thermal; white dwarfs
• ISSN: 0035-8711; 1365-2966
• DOI: 10.1111/j.1365-2966.2010.17800.x

The accretion of matter on to intermediate polar white dwarfs (IPWDs) seems to provide attractive conditions for acceleration of particles to high energies in a strongly magnetized turbulent region at the accretion disc inner radius. We consider possible acceleration of electrons and hadrons in such region and investigate their high-energy radiation processes. It is concluded that accelerated electrons lose energy mainly on synchrotron process producing non-thermal X-ray emission. On the other hand, accelerated hadrons are convected on to the white dwarf (WD) surface and interact with dense matter. As a result, high-energy γ-rays from decay of neutral pions and secondary leptons from decay of charged pions appear. We show that GeV-TeV γ-rays can escape from the vicinity of the WD. Secondary leptons produce synchrotron radiation in the hard X-rays and soft γ-rays. As an example, we predict the X-ray and γ-ray emission from IPWD V1223 Sgr. Depending on the spectral index of injected particles, this high-energy emission may be detected by the Fermi Large Array Telescope and/or the future Cherenkov Telescope Array observatory.