X-ray emission properties from Circinus X-1

Abstract

The X-ray activity of Circinus X-1, a periodically flaring source, was studied using observational data from the all-sky monitor onboard the Rossi X-ray Timing Explorer orbital observatory in the 2–12 keV energy band. The cross-correlation analysis of the 1 day averaged data set obtained in 2001 has confirmed the fundamental 16.6 day orbital period. The variability pattern of source emission in September–November 2005 has a complicated structure that may be explained by X-ray emission pressure on the accretion disc and periodically ejected matter. The spectral analysis of X-ray emission has revealed the source behaviour in high- and low-activity states that may be caused by differential absorption of emission by the dynamically changed environment in a close binary system.