Iron line fluorescence models for GX301 – 2

Abstract

Fluorescence models are applied to iron line observations of GX301 – 2. The dependence of equivalent width on column density can be fairly well described by a spherically symmetric fluorescence model. However, a decrease of fluorescence efficiency as source intensity increases is observed, which is not described by the simple model. The efficiency decrease may be due to a luminosity-dependent accretion geometry. Correction of the equivalent widths for the luminosity-dependence improves the agreement with the spherical model. Small residual deviations of the data from the model are likely, due to inhomogeneities.