Tests of outflow as explanation for the spin fitting problem in continuum-fitting method
Abstract
The determination of the spins of black holes in some X-ray binaries for a range of luminosities done with the use of advanced fully relativistic disk models leads to a paradox: the spin of decreases with the rise in luminosity. Physically, any significant evolution of the spin during the set of observations is impossible. Therefore, the apparent decrease of the spin must be the artefact of the adopted model. We analyse whether this effect might be explained by an outflow from the innermost part of an accretion disk. We find that relatively smooth radial outflows, without explicit dependence on the Eddington ratio do not provide the requested effect. However, we can recover the observed trends with a simple model of an inner cut-off disk which depends on the luminosity. The position of the inner radius must increase linearly with the Eddington ratio. The physical interpretation of such a model is that either most of the material has to be removed from the disk in a form of a wind or a jet, or at least most of the energy has to be removed, leaving behind the cold non-radiating flow close to the black hole horizon.
- Publication:
-
The Extremes of Black Hole Accretion
- Pub Date:
- July 2015
- Bibcode:
- 2015ebha.confE.121Y