Broad emission lines for negatively spinning black holes

TL;DR

This paper introduces an advanced model for calculating emission line profiles from accretion disks around rotating black holes, accounting for different spin orientations and enabling flexible, efficient data analysis.

Contribution

It presents a new computational scheme that models emission lines from accretion disks with arbitrary emissivity and limb darkening, including both prograde and retrograde black hole spins.

Findings

The model accurately reproduces line profiles for various disk configurations.

The code reduces computational data requirements compared to existing models.

It facilitates improved interpretation of X-ray observational data.

Abstract

We present an extended scheme for the calculation of the profiles of emission lines from accretion discs around rotating black holes. The scheme includes discs with angular momenta which are parallel and antiparallel with respect to the black hole's angular momentum, as both configurations are assumed to be stable (King et al., 2005). We discuss line shapes for such discs and present a code for modelling observational data with this scheme in X-ray data analysis programs. Based on a Green's function approach, an arbitrary radius dependence of the disc emissivity and arbitrary limb darkening laws can be easily taken into account, while the amount of precomputed data is significantly reduced with respect to other available models.