Influence of the gravitational darkening effect on the spectrum of a hot, rapidly rotating neutron star. II. Iron lines

Abstract

Rapidly rotating neutron stars are similar to highly flattened ellipsoids. Observed spectra of flattened stars must exhibit effects of non spherical shape and the gravitational darkening. We examined in detail the influence of both effects on the observed central energies and profiles of lines of highly ionized iron, FeXXV and FeXXVI. We note that the gravitational darkening effect do not change the central energy of lines. What is important, spectra of neutron stars that rotate with different frequencies and are seen at various inclinations angles differ significantly. The appearance and the depth of lines strongly depends on the parameters like the inclination angle of the star or the frequency of the star rotation. In this paper we clearly show that the gravitational darkening effect should be included in realistic model of the atmospheres of the neutron stars.

9 pages, 8 figures

References in corpus (7)

• Evidence of a Broad Relativistic Iron Line from the Neutron Star Low-Mass X-ray Binary Serpens X-1
• Universality of the Acceleration Due to Gravity on the Surface of a Rapidly Rotating Neutron Star
• Absorption features in the spectra of X-ray bursting neutron stars
• The surface of rapidly-rotating neutron stars: implications to neutron star parameter estimation
• Rotationally and tidally distorted compact stars A theoretical approach to the gravity-darkening exponents for white dwarfs
• Broad-band spectral analysis of LMXB 2S 0921-63 with Suzaku
• Influence of the gravitational darkening effect on the spectrum of a hot, rapidly rotating neutron star