Astrophysical black holes Chris Reynolds Department of Astronomy

Astrophysical black holes Chris Reynolds Department of Astronomy 1

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

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Observational evidence for black holes Early X-ray observations [1965] discovered a powerful X-ray source in Cygnus l Cygnus X-1 l – 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 – 2 kpc away 5

How do we know the black hole mass? Period 5. 6 days l K = V sin i = 75 km/s l Newtonian analysis… l – MBH>f – Cyg X-1… f=0. 24 MBH Feed in knowledge of i and companion mass… M=7 -13 Msun l 6 “golden” cases with f>3 Msun l Brocksopp et al. (1998) 6

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Strong evidence for a 3 -4 million solar mass BH at the Galactic Center (closest stellar approach only 40 AU!) A. Ghez (UCLA) 9

X-ray studies of black holes Chandra+VLA image of GC (Baganoff et al. 2001) 10

3 C 273 (Quasar) LX ~1038 W MCG-6 -30 -15 (Seyfert gal) (LX~1036 W) 11

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l X-ray “reflection” imprints well-defined features in the spectrum 13

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

MCG-6 -30 -15 Suzaku (Miniutti et al. 2006) 16

Systematic surveys of the XMM archive are showing that ~1/2 of type-1 AGN show broad iron lines (largely confirming ASCA results) NGC 2992 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. ) 17

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XMM analysis of MCG-6 -30 -15 Assuming no emission from within rms a>0. 987 (formal 90% limit) Brenneman & Reynolds (2006) 19

Black Hole Quasi-periodic oscillations l High-frequency QPOs – Comparable frequency to orbital frequency in inner accretion flow – Often found in pairs with 3: 2 ratio l Stable frequencies – probably determined by gravitational potential – Could be an excellent probe of the mass and spin!! 20

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QPO theory Lack of standard QPO theoretical framework is problem l Global modes of accretion disk l – “Diskoseismology”; Wagoner, Nowak, Kato… – Produce g-, p-, and c-modes – Linear theory… no natural explanation for 3: 2 ratio l Resonance model – Parametric resonance between vertical/radial epicyclic frequencies (Abramowicz & Kluzniak) – Source of free energy? Fundamental g-mode (Nowak & Wagoner) Movie by Mike Nowak 23

The Future of BH X-ray Studies Dynamical timescale variability… probes orbital motions in accretion disk Armitage & Reynolds (2004) 24

Powerful probe of turbulent disk physics. Also, arcs approximately trace test-particle Keplerian orbits in = plane. Iwasawa et al. (2004) 25

Light crossing timescale allows reverberation effects to be studied. 26

Chandra Deep Field 27

Constellation-X simulations… Simulated 100 ks; F 2 -10=10 -12 erg/s/cm 2 Simulated 1 Ms; z=1; F 2 -10=10 -14 erg/s/cm 2 ~4 such source per Con-X field 28

Imaging a black hole mm-VLBI 29

Imaging a black hole Micro-arcsecond X-ray Imaging Mission (MAXIM) HST (0. 1 arcsec) MAXIM (0. 05 -arcsec) 30

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 A scalable MAXIM concept. • Offers more optimal UV-Plane coverage- Less dependence on Detector Energy Resolution • Each Module, self contained- Lower Risk. 31