Cen x-3 as seen by MAXI during six years

TL;DR

This study analyzes six years of MAXI/GSC X-ray observations of Cen X-3, examining its light curve, spectral properties, and orbital dynamics to understand accretion processes and stellar wind interactions.

Contribution

It provides detailed spectral and timing analysis of Cen X-3 over six years, identifying QPOs and modeling the emission with two spectral models, enhancing understanding of accretion and wind interactions.

Findings

Estimated orbital period and superorbital QPOs.

Spectral models fit well with partial absorption and power-law components.

High X-ray luminosity suggests accretion beyond stellar wind alone.

Abstract

The aim of this work is to study both light curve and orbital phase spectroscopy of this source taking advantage of the MAXI/GSC observation strategy. We have investigated the spectral and light curve properties of the X-ray emission from Cen X-3 along the binary orbit. These studies allow delimiting the stellar wind properties and its interactions with the compact object. A timing analysis of light curves in different energy bands was carried out. From the analysis of the light curve, we have estimated the orbital period of the binary system and also found possible QPOs around a superorbital period of $P_\mathrm{superorb} = 220\pm 5$ days. Both orbital phase-averaged and phase-resolved spectra were extracted and analysed in the 2.0-20.0 keV energy range. We have defined and compared the high and low states spectra with the averaged spectrum. Two models have described spectra satisfactorily, a partial absorbed Comptonization of cool photons on hot electrons plus a power law and a partial absorbed blackbody plus a power law, both modified by adding Gaussian lines. The radius of the blackbody emitting area has been determined and the high value of the X-ray luminosity in the averaged spectrum indicates that the accretion mode is not only due to the stellar wind.