Transcript Future X-ray studies of black holes

Black Hole Physics with
Constellation-X
Chris Reynolds
Department of Astronomy
University of Maryland
College Park
Outline

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 Accretion
Get geometrically-thick disk
with complex flows if
accretion rate is…
< ~0.01 of Eddington rate
or
> Eddington rate
QuickTime™ and a
YUV420 codec decompressor
are needed to see this picture.
John Hawley
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
strong 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
No light bending
Line profiles encode host
of effects including
strong light bending.
With light bending
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
(Remit2Rg, Rhorizon1Rg)
MCG-6-30-15 : AGN with very well studied “broad iron line”
GX339-4 (stellar-mass BH) w/Suzaku
(J.Miller, C.Reynolds et al. 2008)
III : Constellation-X and black hole spin
Rapidly-spinning
Non-spinning
KERRDISK model
Brenneman & Reynolds (2006)
• 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)
Constellation-X simulation; 1 million photons in 2-10keV band
Constrains a=0.900.05 for amodel=0.90
• 10Ms program will yield 200-300 AGN spins
• Easily obtain spin of every accessible stellarmass BH that goes into outburst
Need 15ks to get this spectrum for a bright AGN
Mergers
Volonteri et al. (2005)
Accretion
M87 / VLA (NRAO)
IV : Constellation-X and the Kerr Metric
Iron line intensity as function of energy and time.
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Arcs trace orbits of disk
material around black
hole… can be compared with
predicted GR orbits
Armitage & Reynolds (2003)
Con-X simulation
Theoretical
(assuming
3x107 Msun black hole)
Relativistic iron line reverberation
Energy
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Time
Transfer function encodes flare-position as well
as geometry of space-time
Reynolds et al. (1999)
Young & Reynolds (2000)
Summary


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 Accretion

Define dimensionless mass accretion rate

Three regimes of accretion…
1.
2.
3.
<10-2 : Hot, quasi-spherical, inefficient flow (e.g.,
Galactic Center, low-state stellar-mass BHs)
10-2<<1 : Thin, radiatively-efficient disk (e.g., many
AGN, high-state stellar-mass BHs)
 >1 : Radiation-pressure dominated, thick disk
(powerful quasars, ULXs?, SS433?)
Density
slice
Bphi
Reynolds &
Miller (2008)
A procedure for testing the Kerr
Metric

Fit each track for (r,a)
assuming Kerr metric
– Kerr metric 
a(r)=constant,
M(r)=constant
Currently developing track
simulations and fitting tools
to judge sensitivity
r=3rg; a=0.95; M=3107 Msun
R=1000rg
R=100rg
R=30rg
R=10rg
R=6rg
Disk
Inclination
Inner edge of
disk (spin)
Gallery of selected broad iron lines
MCG-6-30-15
MCG-5-23-16
NGC4151
GX339-4
NGC2992
IRAS18325
Fairall 9
3C382
GRS1915+105
PG1211
NGC3516
XTEJ1550
Mrk766
Similar line profiles from
stellar-mass and supermassive black hole
systems… demonstrates
insensitivity of line profile
to mass
Cygnus X-1
Improving constraints on relativistic Fe K line
variability by adding high energy response
MCG -6-30-15 for 2ks
Torb=5ks for 107 M
BH at 6Rg.
MCG -6-30-15 for 10ks
Simulations with
4xSXT (Ir coating) +
single HXT
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…


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
continuum
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…
Spin constraints from iron line
technique (90% confidence)…
• MCG-6-30-15, a>0.94
• GX339-4, a=0.930.05
Dabrowski et al. 1997
Brenneman & Reynolds 2006
Reis et al. 2008
Reynolds & Fabian 2008
Miller et al. 2008
no combined iron
combined iron 
iron line emission
Keplerian orbit of a single “hot spot”
a=0.98
i=30o
R=15
R=6
R=2.5
R=3
R=30
Radio loudness (Lrad/LB)
The radio-quiet/radio-loud dichotomy in AGN
Rapid spinners?
Slow spinners?
Accretion rate (Eddington Units)
Sikora et al. (2007)
MCG-6-30-15
XMM-Newton/350ks
Simple power-law fit
(excluding 3-8keV)
• Formal limit on spin a>0.987
• Reasonable deviations from
ISCO conjecture  a>0.94
Brenneman & Reynolds (2006)