Photon Propagation around Compact Objects and the Inferred Properties of Thermally Emitting Neutron Stars

Abstract

Anomalous X-ray pulsars, compact nonpulsing X-ray sources in supernovaremnants, and X-ray bursters are three distinct types of sources forwhich there are viable models that attribute their X-ray spectra tothermal emission from the surface of a neutron star. Inferring thesurface area of the emitting regions in such systems is crucial inassessing the viability of different models and in providing boundson the radii of neutron stars. We show that the spectroscopicallyinferred areas of the emitting regions may be over- or underestimated bya factor of ~30%) is not a strongargument against its identification with a spinning neutron star.