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Astrophysical black holes

Astrophysical black holes. Chris Reynolds Department of Astronomy. Topics. Observational evidence for black holes X-ray studies of strong-gravity region First observational studies of BH spin Future directions. Observational evidence for black holes.

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Astrophysical black holes

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  1. Astrophysical black holes Chris Reynolds Department of Astronomy

  2. Topics • Observational evidence for black holes • X-ray studies of strong-gravity region • First observational studies of BH spin • Future directions

  3. Observational evidence for black holes • Early X-ray observations [1965] discovered a powerful X-ray source in Cygnus • Cygnus X-1 • Binary star system… black hole in orbit around a massive O-star • Black hole mass 7-13 M • X-rays produced due to accretion of stellar wind from O-star • 2kpc away

  4. How do we know the black hole mass? • Period 5.6 days • K = V sin i = 75km/s • Newtonian analysis… • MBH>f • Cyg X-1… f=0.24MBH • Feed in knowledge of i and companion mass… M=7-13Msun • 6 “golden” cases with f>3Msun Brocksopp et al. (1998)

  5. Strong evidence for a 3-4 million solar mass BH at the Galactic Center (closest stellar approach only 40AU!) A. Ghez (UCLA)

  6. X-ray studies of black holes Chandra+VLA image of GC (Baganoff et al. 2001)

  7. 3C273 (Quasar) LX ~1038 W MCG-6-30-15 (Seyfert gal) (LX~1036 W)

  8. X-ray “reflection” imprints well-defined features in the spectrum

  9. Relativistic effects imprint characteristic profile on the emission line… Iron line profile in MCG-6-30-15

  10. MCG-6-30-15 Suzaku (Miniutti et al. 2006)

  11. Systematic surveys of the XMM archive are showing that ~1/2 of type-1 AGN show broad iron lines (largely confirming ASCA results) NGC2992 IRAS 18325 (Iwasawa 2004) MCG-5-23-16 (Dewangan 2003) • Also see Suzaku results on broad iron lines at this meeting: • MCG-5-23-16 (Reeves et al.) • NGC 3516 (Markowitz et al.)

  12. XMM analysis of MCG-6-30-15 Assuming no emission from within rms a>0.987 (formal 90% limit) Brenneman & Reynolds (2006)

  13. Black Hole Quasi-periodic oscillations • High-frequency QPOs • Comparable frequency to orbital frequency in inner accretion flow • Often found in pairs with 3:2 ratio • Stable frequencies • probably determined by gravitational potential • Could be an excellent probe of the mass and spin!!

  14. QPO theory • Lack of standard QPO theoretical framework is problem • Global modes of accretion disk • “Diskoseismology”; Wagoner, Nowak, Kato… • Produce g-, p-, and c-modes • Linear theory… no natural explanation for 3:2 ratio • Resonance model • Parametric resonance between vertical/radial epicyclic frequencies (Abramowicz & Kluzniak) • Source of free energy? Fundamental g-mode (Nowak & Wagoner) Movie by Mike Nowak

  15. The Future of BH X-ray Studies Dynamical timescale variability… probes orbital motions in accretion disk Armitage & Reynolds (2004)

  16. Powerful probe of turbulent disk physics. Also, arcs approximately trace test-particle Keplerian orbits in = plane. Iwasawa et al. (2004)

  17. Light crossing timescale allows reverberation effects to be studied.

  18. Chandra Deep Field

  19. Constellation-X simulations… Simulated 1Ms; z=1; F2-10=10-14erg/s/cm2 ~4 such source per Con-X field Simulated 100ks; F2-10=10-12erg/s/cm2

  20. Imaging a black holemm-VLBI

  21. Imaging a black holeMicro-arcsecond X-ray Imaging Mission (MAXIM) HST (0.1 arcsec) MAXIM (0.05 -arcsec)

  22. Current MAXIM concept Group and package Primary and Secondary Mirrors as “Periscope” Pairs ~20,000 km ~500-1000 m Baseline • “Easy” Formation Flying (microns) • All s/c act like thin lenses- Higher Robustness • Possibility to introduce phase control within one space craft- an x-ray delay line- More Flexibility • Offers more optimal UV-Plane coverage- Less dependence on Detector Energy Resolution • Each Module, self contained- Lower Risk. A scalable MAXIM concept.

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