Black Hole Physics with Constellation-X

Black Hole Physics with Black Hole Physics with Constellation-XConstellation-X

Chris Reynolds

Department of AstronomyUniversity of Maryland

College Park

OutlineOutline Black hole accretion

– Using accreting black holes for gravitational physics– The simplicity of thin accretion disks

Probing strong gravity with X-ray spectroscopy– X-ray reflection spectroscopy and broad iron lines– We are studying strong-field gravitation physics today

Constellation-X– Opening-up the physics/astrophysics of black hole spin– New probes of Kerr metric

I : Black Hole AccretionI : Black Hole Accretion

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John Hawley

Get geometrically-thick disk with complex flows if accretion rate is…

< ~0.01 of Eddington rateor> Eddington rate

Reynolds & Miller (2008)

Comparison of disk velocity derived from a 3-d MHD simulation (dotted) with simple test-particle velocity (solid)… confirms analytic result that deviations are O[(h/r)2]

II : X-ray spectroscopy and probes of II : X-ray spectroscopy and probes of strong gravitystrong gravity

X-rays from corona/jet irradiate accretion disks… creates a backscattered spectrum rich in spectral features

Calculations of spectrum emitted by accretion disk in response to X-ray irradiation (Ross & Fabian 2005)

Very similar fluorescence features seen from surface of Sun during X-ray bright solar flare

Line profiles encode host of effects including strong light bending.

No light bending

With light bending

MCG-6-30-15 : AGN with very well studied “broad iron line”

MCG-6-30-15 (supermassive BH) w/Suzaku(Miniutti et al. 2006)

Extremely broad iron line originate from matter very close to rapidly spinning BH (Remit2Rg, Rhorizon1Rg)

GX339-4 (stellar-mass BH) w/Suzaku(J.Miller, C.Reynolds et al. 2008)

III : Constellation-X and black hole spinIII : Constellation-X and black hole spin

Non-spinningRapidly-spinning

• Theoretical assumption : X-ray reflection / iron line emission truncates at the innermost stable circular orbit (ISCO conjecture; confirmed by simulations)

• Black hole spin then determined from extent of “red wing” of broad iron line (independent of BH mass)

KERRDISK modelBrenneman & Reynolds (2006)

Constellation-X simulation; 1 million photons in 2-10keV bandConstrains a=0.900.05 for amodel=0.90

Need 15ks to get this spectrum for a bright AGN

• 10Ms program will yield 200-300 AGN spins• Easily obtain spin of every accessible stellar-mass BH that goes into outburst

Volonteri et al. (2005)

Mergers Accretion

M87 / VLA (NRAO)

Arcs trace orbits of disk material around black hole… can be compared with predicted GR orbits

Iron line intensity as function of energy and time.

TheoreticalCon-X simulation(assuming 3x107 Msun black hole)

IV : Constellation-X and the Kerr MetricIV : Constellation-X and the Kerr Metric

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Armitage & Reynolds (2003)

Relativistic iron line reverberationRelativistic iron line reverberation

Reynolds et al. (1999) Young & Reynolds (2000)

Transfer function encodes flare-position as well as geometry of space-time

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Time

En

ergy

SummarySummary Geometrical and kinematic simplicity of thin accretion

disks allows study of gravitational physics via X-ray spectroscopy

Constellation-X will open the window on the astrophysics of black hole spin– Determine spin for 150-300 supermassive BHs – Distinguish merger vs. accretion scenarios for SMBH growth– Determine spin for every accessible Galactic BH that goes into

outburst… determine natal (birth) spin Constellation-X will allow new probes of the Kerr metric

– Rapid iron line variability used to probe “Keplerian” orbits – Relativistic iron line reverberation reveals photon dynamics close

to the BH

Backup slides

I : Black Hole AccretionI : Black Hole Accretion

Define dimensionless mass accretion rate

Three regimes of accretion…1. <10-2 : Hot, quasi-spherical, inefficient flow (e.g.,

Galactic Center, low-state stellar-mass BHs)2. 10-2<<1 : Thin, radiatively-efficient disk (e.g., many

AGN, high-state stellar-mass BHs)3. >1 : Radiation-pressure dominated, thick disk

(powerful quasars, ULXs?, SS433?)

Reynolds &Miller (2008)

Density slice

Bphi

A procedure for testing the Kerr A procedure for testing the Kerr MetricMetric

Fit each track for (r,a) assuming Kerr metric– Kerr metric

a(r)=constant, M(r)=constant

r=3rg; a=0.95; M=3107 Msun

Currently developing track simulations and fitting tools to judge sensitivity

R=1000rgR=100rgR=30rgR=10rgR=6rg

Disk Inclination

Inner edge of disk (spin)

Gallery of selected broad iron linesGallery of selected broad iron linesMCG-6-30-15

MCG-5-23-16

IRAS18325NGC2992

Fairall 9 3C382

PG1211 NGC3516

NGC4151 Mrk766

GX339-4

GRS1915+105

XTEJ1550

Cygnus X-1

Similar line profiles from stellar-mass and super-massive black hole systems… demonstrates insensitivity of line profile to mass

Improving constraints on relativistic Fe K line variability by adding high energy response

MCG -6-30-15 for 2ks MCG -6-30-15 for 10ks

Simulations with 4xSXT (Ir coating) + single HXT

Torb=5ks for 107 M BH at 6Rg.

Broad line+reflection constraints improved by including a HXE. Even in 2ks, “R” can be constrained to 40% (vs no constraint without HXE) and the iron line parameters to ~30% accuracy (x2 improvement). A modest HXE improves the feasibilty of tracking variations in Fe K and reflection on <orbital timescales.

Observing strategy and sample size…Observing strategy and sample size…

Strategy : target known AGN on the basis of flux and the presence of a broad iron line… “run down the log N - log S curve”

Using HEAO-A1 LogN-LogS…

– f is fraction of sources with broad lines

– nph is number of 2-10keV photons needed for individual measurement

Need precusor survey to identify sources with broad iron lines– Start with suitable parent sample (e.g. Swift/BAT survey)– Snapshot survey of 500 AGN (10Ms total provides sufficient s/n to

determine presence of relativistic iron lines)– Some fraction of this precusor work will be conducted by XMM and

Suzaku beforehand

Black hole spin from thermal accretion disk Black hole spin from thermal accretion disk continuumcontinuum

Frontera et al. (2001)

• Features : applicable in states when iron line is hard to discern. But need to know mass, distance, inclination independently

• Theoretical uncertainty : Precise form of disk spectrum after processing by disk atmosphere. Also relies on ISCO conjecture.

Iron line emission truncates close to ISCO due to steeply rising ionization parameter of the matter…

no combined iron

combined iron iron line emission

Spin constraints from iron line technique (90% confidence)…• MCG-6-30-15, a>0.94• GX339-4, a=0.930.05

Dabrowski et al. 1997Brenneman & Reynolds 2006Reis et al. 2008Reynolds & Fabian 2008Miller et al. 2008

Keplerian orbit of a single “hot spot”Keplerian orbit of a single “hot spot”

a=0.98i=30o

R=30R=3R=2.5R=6R=15

The radio-quiet/radio-loud dichotomy in AGN

Accretion rate (Eddington Units)

Rad

io lo

udne

ss (

L ra

d/L

B)Rapid spinners?

Slow spinners?

Sikora et al. (2007)

MCG-6-30-15XMM-Newton/350ksSimple power-law fit (excluding 3-8keV)

Brenneman & Reynolds (2006)

• Formal limit on spin a>0.987• Reasonable deviations from ISCO conjecture a>0.94