Theory Meets Reality: Accretion Disc Evolution in GRO J1655-40 and LMC X-3 with Relativistic and Non-Relativistic Disc Models

Abstrakt

Black hole X-ray binaries are the ideal environments to study the accretion phenomena in strong gravitational potentials around such compact objects. These systems undergo dramatic accretion state transitions throughout an outburst and analysis of the X-ray spectra is used to probe the properties of the accretion disc and its evolution.

We will present the results from a systematic investigation of TILDE OPERATOR+D911800 spectra obtained by RXTE PCA observations of GRO J1655-40 and LMC X-3 to explore the nature of the accretion disc via non-relativistic and relativistic disc models describing the thermal accretion disc emission in black-hole X-ray binaries. Our results show that the non-relativistic multi-colour disc blackbody model (diskbb) gives significantly (about ~50-60%) higher values for disc temperatures and lower (often unphysical) inner disc radii than relativistic disc models (KERRBB and KYNBB).

We also report a much lower spin of ~0.1 for LMC X-3 than previously predicted ~0.6-0.7 using the updated black hole mass. Additionally, we see clear evidence for a varying inner disc in GRO J1655-40 and highlight the importance of self-consistent modeling of the thermal emission in accreting compact objects, especially when estimating the black hole spin with the continuum-fitting method.

We will discuss the implications of our findings on the interpretation of previous results from global studies with RXTE observations.