Iron K-alpha line profiles driven by non-axisymmetric illumination

Abstract

Previous calculations of Fe K-alpha line profiles are based on axisymmetric emissivity laws. In this paper, we show line profiles driven by non-axial symmetric illumination which results from an off-axis X-ray point source. We find that source location and motion have significant effects on the red wing and blue horn of the line profiles. The disk region under the source will receive more flux, which is the most important factor to affect the line profiles. We suggest that at least part of the variation in Fe K-alpha line profiles is caused by the motion of X-ray sources. Future observations of Fe K-alpha line profiles will provide more information about the distribution and motion of the X-ray sources around black holes, and hence the underlying physics.