Modelling magnetars' high energy emission through Resonant Cyclotron Scattering

Abstract

We present a systematic fit of a model of resonant cyclotron scattering (RCS) to the X and soft gamma-ray data of four magnetars, including anomalous X-ray pulsars, and soft gamma repeaters. In this scenario, non-thermal magnetar spectra in the soft X-rays result from resonant cyclotron scattering of the thermal surface emission by hot magnetospheric plasma. We find that this model can successfully account for the soft X-ray emission of magnetars, while an additional component is still required to model the hard X-ray persistent magnetar emission recently discovered by INTEGRAL. The latter is an important component in terms of magnetars' luminosity, and cannot be neglected when modelling the soft X-ray part of the spectrum.