X-ray thermal radiation from hot polar cap in pulsars

Abstract

We discuss the partially screened gap (PSG) model of the pulsar inner accelerator, which implies that the temperature of the polar cap surface is almost equal to the so called critical temperature defined by the strength of the magnetic field at the polar cap surface. Observations of thermal X-ray emission reveal an important correlation between the hot spot area and its surface temperature, both derived from the blackbody fit. The hot spot surface area is generally much smaller than that of the conventional polar cap, implying that geometry and strength of the actual surface magnetic field differ essentially from the pure dipolar field. We believe that major characteristics of the pulsar radiation, including correlation between observed features of X-ray and radio emissions can be naturally explained within the framework of the PSG model.