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Astrophysical black holesAstrophysical black holes

Chris ReynoldsDepartment of Astronomy

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TopicsTopics

Observational evidence for black holesX-ray studies of strong-gravity regionFirst observational studies of BH spinFuture directions

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Observational evidence for Observational evidence for black holesblack 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

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How do we know the black How do we know the black hole mass?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)

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9A. Ghez (UCLA)

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

10Chandra+VLA image of GC (Baganoff et al. 2001)

X-ray studies of black holesX-ray studies of black holes

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MCG-6-30-15 (Seyfert gal)(LX~1036 W)

3C273 (Quasar)LX ~1038 W

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

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Relativistic effects imprint characteristic profile Relativistic effects imprint characteristic profile on the emission line…on the emission line…

Iron line profile inMCG-6-30-15

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

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Also see Suzaku results on broad iron lines at this meeting:• MCG-5-23-16 (Reeves et al.)• NGC 3516 (Markowitz et al.)

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

MCG-5-23-16 (Dewangan 2003)

NGC2992

IRAS 18325 (Iwasawa 2004)

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19Brenneman & Reynolds (2006)

Assuming no emission from within rms

a>0.987 (formal 90% limit)

XMM analysis of MCG-6-30-15

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Black Hole Quasi-periodic Black Hole Quasi-periodic oscillationsoscillations

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!!

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QPO theoryQPO 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

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The Future of BH X-ray StudiesThe Future of BH X-ray Studies

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Armitage & Reynolds (2004)

Dynamical timescale variability… probes orbital motions in accretion disk

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Powerful probe of turbulent disk physics. Also, arcs approximately trace test-particle Keplerian orbits in = plane.

Iwasawa et al. (2004)

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Light crossing timescale allows reverberation effects to be studied.

27Chandra Deep Field

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Constellation-X simulations…Constellation-X simulations…

Simulated 100ks; F2-10=10-12erg/s/cm2 Simulated 1Ms; z=1; F2-10=10-14erg/s/cm2

~4 such source per Con-X field

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Imaging a black holeImaging a black holemm-VLBImm-VLBI

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Imaging a black holeImaging a black holeMicro-arcsecond X-ray Imaging Micro-arcsecond X-ray Imaging

Mission (MAXIM)Mission (MAXIM)

HST (0.1 arcsec)

MAXIM (0.05 -arcsec)

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~20,000 km

Current MAXIM conceptCurrent MAXIM conceptGroup and package Primary and Secondary Mirrors as “Periscope” Pairs

•“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.

~500-1000 m Baseline

A scalable MAXIM concept.