Black Holes: A Laboratory for Testing Strong Gravity by Cosimo Bambi

Author:Cosimo Bambi
Language: eng
Format: epub
Publisher: Springer Singapore, Singapore

(8.3)

With the formalism of the transfer function, we can thus separate the calculations involving the astrophysical model (reflection spectrum) from those involving the relativistic effects on the photons (Doppler boosting, gravitational redshift, light bending). The function may depend on the background metric (see below the case of the lamppost set-up), but it is a minor job and the transfer function formalism is very convenient for the calculations.

While it is necessary to fit the full reflection spectrum to study a source and determine its parameters, in this section we will restrict the attention to the iron K line only. This will permit to better understand the impact of the strong gravity region on the shape of the reflection spectrum.

The shape of the line is primarily determined by the background metric, the geometry of the emitting region, the disk emissivity, and the disk’s inclination angle with respect to the line of sight of the distant observer. In the Kerr background, the relativistic emission line profile emitted by an accretion disk illuminated by an X-ray corona with arbitrary geometry is typically parametrized by the black hole spin , the inner and the outer edge of the emission region and , and the viewing angle i. The intensity profile may be modeled as a power-law , where the emissivity index q is a free parameter to be determined by the fit. A more sophisticated choice is to assume a broken power-law, i.e.

Download

Copyright Disclaimer:
This site does not store any files on its server. We only index and link to content provided by other sites. Please contact the content providers to delete copyright contents if any and email us, we'll remove relevant links or contents immediately.