1. Lecture 20 Accretion spectrum Gravitational redshift Iron Kα line
Spinning black holes

2. Spectrum produced by standard geometrically thin, optically thick accretion disk

3. Models of accretion spectra for various central masses and accretion rates

4. Effective potential in Schwarzschild metric

5. Orbits in a Schwarzschild metric

6. X-ray spectral features

7. Formation of Kα doublet

8. Monte Carlo simulation of a reflection
spectrum from a slab of uniform density
neutral matter with solar abundances
Main components of the X-ray
Spectrum of an unobscured
Accreting BH

9. Photon shifts
Photons from the accretion disc are redshifted because of the Gravitational redshift and the Doppler transverse effect, and
blueshifted /redshifted by the Doppler effect when the matter is approaching/receding

10. Doppler boosting The quantity Iυ/υ3 is a Lorentz invariant
Therefore, the blueshifted radiation is
brighter (Doppler boosting), the
redshifted one is fainter

11. X-ray spectral features
The abovementioned
SR and GR effects
modify the line profile
in a characteristic and
well-recognizable way
(Fabian et al. 2000)

12. Relationship between ISCO radius and spin
Schwarzschild BH
Maximal Kerr BH

13. Dependence of the line profile on the
Emissivity profile of the disk:
R^-q
The steeper the emissivity, the broader
The line profile because more emphasis
Is given to the innermost radii, where the
GR effects are strongest
Dependence of the line profile on the
observer inclination

14. MCG (37 Mpc)
a>0 !!!
ASCA (Tanaka et al. 1995)

15. XMM-Newton spectrum of Seyfert 1 MCG-6-30-15
Fabian et al. 2002

16. BIBLIOGRAPHY A.C. Fabian, K. Iwasawa, C.S. Reynolds, & A.J. Young 2000
Broad iron lines in Active Galactic Nuclei, PASP, 112, 1145
A.C. Fabian & G. Miniutti 2008
The X-ray spectra of accreting Kerr black holes
In: The Kerr Spacetime: Rotating Black Holes in General Relativity
Eds. D.L. Wiltshire, M. Visser, S. M. Scott (CUP)
(astro-ph/ )
J. Frank, A.R. King, D.J. Raine 1985
Accretion Power in Astrophysics
Cambridge University Press
Ghisellini 2013
Radiative Processes in High Energy Astrophysics
Lecture Notes in Physics, Vol. 873
Springer
C.S. Reynolds & M.A. Nowak 2003
Fluorescent iron lines as a probe of astrophysical black hole systems
Physics Reports, 377, (astro-ph/ )
G.E. Romero & G.S. Vila 2014
Introduction to Black Hole Astrophysics
Lecture Notes in Physics Vol. 876