Nonlinear and Geometric Properties of Accreting Compact Sources Based on Spectral and Timing Analyses

Abstract

We study the spectro-temporal properties of the black hole X-ray binaries (BHXBs) GRS 1915+105 and IGR J17091-3624 with data from RXTE, Chandra and XMM-Newton. From the analysis result, we propose models of accretion modes in terms of known accretion classes that might be responsible for the different correlated spectral states with temporal classes, namely: Keplerian disc flow (Shakura and Sunyaev, 1973a), slim disc flow (Abramowicz et al., 1988), advection dominated accretion flow or ADAF (Narayan and Yi, 1994) and general advective accretion flow or GAAF (Rajesh and Mukhopadhyay, 2010). We further posit that accretion rate must play an important role in transition between these states. While GRS 1915+105 exhibits all four modes, in IGR J17091-3624, only two of the modes ADAF and slim disc are evident, although the effect of Poisson noise cannot be ruled out. Thus, we infer that while both sources show a lot of similarities in their lightcurves, the underlying nonlinear dynamical properties of their accretion flows may be different. With long, continuous optical/UV and X-ray data from AGNs, 134 Summary and future prospects this model can be tested, as any consistent result will throw more light on how the mechanisms at work in BHXBs and AGNs are related. The energy spectra of the Seyfert 1 AGN Zw 229.015 reveals the presence of strong soft X-ray emission below 1keV in excess of the primary X-ray power-law. In an attempt to probe the plausible origin of the soft excess, we apply four different models, namely: multicolour disc blackbody (Mitsuda et al., 1984; Makishima et al., 1986), smeared wind absorption (Gierli´nski and Done, 2004), thermal Comptonisation (Titarchuk, 1994) and relativistically blurred reflection (Ross and Fabian, 2005) models. We find that both thermal Comptonisation and relativistically blurred reflection models provide acceptable explanation to the origin of the soft X-ray excess. Further, based on soft/hard X-ray time lag, we constrain the size of its corona to be and#8764; 20Rg a value which is...