strong field effects on emission line profiles: kerr black holes and warped accretion disks
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Strong field effects on emission line profiles:
Kerr black holes and warped accretion disks
9th Group Seminar
Yan Wang 王炎Dept. of Astronomy, Nanjing University
Dec. 2, 2010
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
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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.
• Motivationsmeasure black hole spin; study the structure of accretion disk
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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).
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Photon trajectories in the Kerr spacetimeIn the standard Boyer-Lindquist coordinates, the Kerr metric can be written as:
Jason Dexter and Eric Agol (UW-Seattle), “geokerr”. arXiv:0903.0620 6
Geometric and kinematic structure of the warped disk
where
For detailed kinematic structure, see my notes. 7
a=0.998, \theta=70^o, \phi=180^o, (r_ms, 10, 50), q=-2
Emission line profiles and disk images
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a=0.998, \theta=30^o, (r_ms, 10, 50), q=-2
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a=0.998, \theta=70^o, (r_ms, 10, 50), q=-2
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a=0.998, \theta=70^o, \phi=180^o, (r_ms, 10, 50), q=-2
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a=0.998, \theta=70^o, \phi=0^o, (r_ms, 10, 50), q=-2
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Disk image (not finished yet)
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Semi-analytic, FWZI/FWHI limits
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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)• … … …
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Appendix A: Expression of g for the warped disks
For expression of g, see my notes.
Acknowledgment and references.
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Thank You !!
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