Talk detail

Participant	Beloborodov, Andrei
Institution	Physics Dept., Columbia University - 538 W 120th Street - New York - NY - USA

Session	SF1	Accepted		Order	Time
Talk	Oral abstract	Title	Magnetospheric activity of magnetars
Co-authors
Abstract	Recent progress in understanding persistent nonthermal activity of magnetars will be discussed. The nonthermal emission is generated by continual electric discharge in the nonpotential magnetosphere deformed by shear motions of the stellar surface. Large active magnetic loops around magnetars must be filled with outflowing particles that interact with radiation via resonant scattering and spawn electron-positron pairs. The outflow energy is processed into copious e+/e- pairs until the plasma enters the outer parts of the loop where the magnetic field is reduced below 10^13 G. In the outer zone, the photons scattered by the outflow do not convert to pairs and the outflow radiates its energy away. The loop radiation is shown to form a distinct hard X-ray component in the magnetar spectrum that peaks around 1 MeV. It creates a pulsating flux of hard X-rays, modulated by the rotation of the star. Excessive deformation of the magnetosphere leads to its catastrophic relaxation and a powerful X-ray flare. First numerical experiments show how this relaxation occurs and how it changes the magnetic wind from the rotating magnetar and its spindown rate.