XMM-Newton Observations of X-ray Pulsar Cen X-3

TL;DR

This study analyzes XMM-Newton data of the X-ray pulsar Cen X-3, revealing iron emission lines, their variations, and modeling the accretion disk, but does not detect the Fe XXV triplet due to instrument limitations.

Contribution

First detailed modeling of iron emission lines in Cen X-3 using XMM-Newton data, including disk geometry and line variability analysis.

Findings

Detected Fe I K alpha, Fe XXV, and Fe XXVI lines within 6.4-7.0 keV.

Observed intensity variations of iron lines during orbital motion.

Did not detect Fe XXV triplet due to instrument resolution limits.

Abstract

We present the results of our study of X-ray pulsar Cen X-3 using XMM-Newton observations. The light curve and the spectrum for this observations were built and Fe triplet within 6.5-7 keV region was detected. The geometric model of relativistic accretion disk for iron emission lines Fe I K alpha, Fe XXV and Fe XXVI in 6.4-7.0 keV region was applied. The values of disc inclination, inner and outer radii of the disc and mass of the central compact object (neutron star) were obtained. Intensity variations of these lines during orbital motion were also detected. The largest variation was detected for Fe I K alpha line, that agrees with the results of other authors. These results conform the model in which Fe I K alpha line forms in hot plasma of accretion disc and highly ionized iron lines form in outer regions of binary system. Probably the most interesting feature of Cen X-3 spectrum is Fe XXV triplet which was found by Iaria et al. (2005) from Chandra data analysis. We did not find this triplet in our analysis of XMM-Newton data and explain its absence by the insufficient energy resolution of XMM-Newton instruments.