Abstract
We will present a detailed investigation of X-ray spectral models used to fit the thermal accretion disk emission in black-hole X-ray binaries. We fit 2000 RXTE observations of GRO J1655-40 and LMC X-3 to explore the nature of the accretion disk in strong gravitational fields via non-relativistic and relativistic disk models.
We find that the non-relativistic multi-color disk blackbody model (diskbb) gives significantly (about 50-60%) higher values for disk temperatures and lower (often unphysical) inner disk radii than relativistic disk models. Our study clearly shows 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 interpretation of previous results with RXTE observations as well as our planned extension to a wider population of accreting black holes and application to more sensitive X-ray data (XMM-Newton, NICER, Chandra).