Strong field effects on emission line profiles: Kerr black holes and warped accretion disks

1. 9th Group Seminar Strong field effects on emission line profiles: Kerr black holes and warped accretion disks Yan Wang 王炎 Dept. of Astronomy, Nanjing University Dec. 2, 2010

2. Outline • Introduction • Photon trajectories in the Kerr spacetime • Geometric and kinematic structure of the warped disk • Emission line profiles and disk images (results) • Semi-analytic, FWZI/FWHI limits • Summary and Conclusions • Appendix A

3. Introduction • Backgrounds • Accretion power serves as an important source of energy in astrophysics, especially in X-ray binaries (XRBs) and active galactic nuclei (AGNs). Accretion onto both stellar mass black holes in XRBs and supermassive black holes ( 10^6− 10^9M_⊙) in AGNs is believed to proceed through an accretion disk, which is truncated at the inner most stable circular orbit (ISCO)…cold disk, corona, external hard X-ray illumination, fluorescence line, warped disk (misalignment) justification. • Motivations • measure black hole spin; study the structure of accretion disk

4. Relativistic line models: a standard thin disk orbiting around a Schwarzschild black hole calculated by Fabian et al. (1989); a standard thin orbiting an extreme Kerr black hole Laor (1991) and Bromley et al. (1997); a standard thin orbiting a Kerr black hole(no \phi) (Fanton et al. 1997); warped disk orbiting a Schwarzschild black hole (Hartnoll & Blackman 2000, Wu et al. 2008); disk with spiral velocity structure orbiting a Schwarzschild (Hartnoll & Blackman 2002).

6. Photon trajectories in the Kerr spacetime In the standard Boyer-Lindquist coordinates, the Kerr metric can be written as: Jason Dexter and Eric Agol (UW-Seattle), “geokerr”. arXiv:0903.0620

7. Geometric and kinematic structure of the warped disk where For detailed kinematic structure, see my notes.

8. Emission line profiles and disk images a=0.998, \theta=70^o, \phi=180^o, (r_ms, 10, 50), q=-2

9. a=0.998, \theta=30^o, (r_ms, 10, 50), q=-2

10. a=0.998, \theta=70^o, (r_ms, 10, 50), q=-2

11. a=0.998, \theta=70^o, \phi=180^o, (r_ms, 10, 50), q=-2

12. a=0.998, \theta=70^o, \phi=0^o, (r_ms, 10, 50), q=-2

13. Disk image (not finished yet)

14. Semi-analytic, FWZI/FWHI limits

15. Summary and Conclusions • We present here, for the first time, the emission line profiles from a warped disk orbiting around a Kerr black hole. • The calculation is general, details are concerned with trajectories of both photons and particles. • Multiple peaks, long red tails close to infinite redshifting… • Changing of shape for different azimuthal angles for a fixed inclination, and for different inclinations • Differences between twist-free and twisted warped disks • Flux incident onto disk from source (source shadowing) • … … …

16. Appendix A: Expression of g for the warped disks For expression of g, see my notes. Acknowledgment and references.

17. Thank You !!