Transcript Project Status

XIV Advanced School on Astrophysics
Topic III: Observations of the Accretion Disks of
Black Holes and Neutron Stars
Ron Remillard
Kavli Institute for Astrophysics and Space Research
Massachusetts Institute of Technology
http://xte.mit.edu/~rr/XIVschool_III.1.ppt
Topic III: General Outline
III.1 Accretion States of Black Hole Binaries (I)
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X-ray Astronomy and Identification of Accreting Binaries
Properties of Compact Objects and Accretion Disks
Different X-ray States in Black Hole Binaries
Thermal State: Thermal Radiation from the Accretion Disk
III.2 Accretion States of Black Hole Binaries (II)
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Observations of the Black Hole Hard State
Observations of the Steep Power Law State
Transients in Quiescence
X-ray Quasi-Periodic Oscillations in Black Hole Binaries
III.3 Accretion Disks around Neutron Stars
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Timing Properties of Accreting Neutron Stars
Observations of Atoll Type Sources
New Interpretations for Z Type Sources
III.1 Accretion States of Black Hole Binaries (I)
Introduction to X-ray Binary Systems
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Context for X-ray Astronomy
Classifications of X-ray Binaries
Black Holes, Neutron Stars, & Accretion Disks
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Physical Properties
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Measurement Techniques
X-ray States of Black Hole Binaries
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Spectral/Timing Evolution of Accreting Black Holes
Illustrations of Black Hole X-ray States
Thermal State: Hot Accretion Disk
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Expectations and Definition of the Thermal State
Building the Paradigm for the Thermal State
X-ray Photons
Wien’s Displacement Law (1893)
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--- 10 Angstroms
(wavelength (l) of max. energy flux in I(n))
is very hot !
T = 5 x 107 oK / lmax (Angstroms)
Wilhelm Carl Werner Otto Fritz Franz Wien
X-rays: Photons 0.6-12 Angstroms  Energies 20-1 keV
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Thermal Equivalent kT = 4 to 80 million oK
Heating mechanisms  non-thermal processes
synchrotron radiation (high energy e- in B field)
inverse Compton (photon upscattered by high energy e-)
Window for Astrophysics from Space
Photon transmission
through the Galaxy
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X-rays: recover
long-distance view at
E > 1 keV
X-ray Telescopes in Space
Chandra (NASA Great Observatory)
Rossi X-ray Timing Explorer (NASA)
XMM-Newton (European Space Agency)
MIRAX (small mission planned by Brazil)
Brightest X-ray Sources (10 to 10-3 Crab)
Milky Way Sources
primary X-spectrum
Accreting Neutron Stars
Atoll- and Z-sources
Accretion-powered Pulsars
Isolated Pulsars
Accreting Black Holes
Supernova Remnants
thermal ; non-thermal hard state
non-thermal
mixed types
thermal + non-thermal states
thermal (shocks)
Stellar Coronae
Accreting White Dwarfs
thermal (B instability)
thermal
Extragalactic
Active Galactic Nuclei
Blazars
Clusters of Galaxies
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non-thermal (hard state)
non-thermal (jets)
thermal (bremsstrahlung)
1.0 Crab ~ 2.4x10-8 erg cm-2 s-1 at 2-10 keV
Brightest X-ray Sources (10 to 10-3 Crab)
Milky Way Sources
primary X-spectrum
Accreting Neutron Stars
Atoll- and Z-sources
Accretion-powered Pulsars
Isolated pulsars
Accreting Black Holes
Supernova Remnants
thermal ; non-thermal hard state
non-thermal
mixed types
thermal + non-thermal states
thermal (shocks)
Stellar Coronae
Accreting White Dwarfs
thermal (B instability)
thermal
accretion disk
yes
yes
yes
Extragalactic
Active Galactic Nuclei
Blazars
Clusters of Galaxies
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non-thermal (hard state)
non-thermal (jets)
thermal (bremsstrahlung)
1.0 Crab ~ 2.4x10-8 erg cm-2 s-1 at 2-10 keV
yes
yes
Binary Evolution for Accreting Compact Objects
Scenario 1: Roche Lobe overflow
• More massive star dies first
• Binary separation can shrink
(magnetic braking and/or grav. radiation)
• Companion may evolve and grow
Common for Low-Mass (Companion)
X-ray Binaries (LMXB)
Scenario 2: Stellar Wind Accretion
• More massive star dies first
• Stellar wind captured
(with possible inner accretion disk)
Common for High-Mass (Companion)
X-ray Binaries (HMXB)
Properties of Black Holes
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mass: Mx
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Spin parameter:
a* = cJ / GMx2
(J = angular momentum ; dimensionless 0 < a* < 1 ; Erot < 0.29 M)
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charge: assume Qx = 0 (local plasma prevents charge buildup)
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event horizon ! (math. surface of ‘no escape’)
(see Shapiro & Teukolsky 1983; Narayan 2004)
Can spin be measured?
Will quantitative, GR-based astrophysics be successful?
Accretion disk observations / accretion theory
are the primary tools!
Measuring Masses of Compact Objects
Dynamical study: compact objectx and companion starc
(for binary period, P, and inclination angle, i )
Kepler’s 3rd Law: 4 p2 (ax + ac)3 = GP2 (Mx + Mc)
center of mass:
Mx ax = Mc ac
radial velocity amplitude
Kc = 2 p ac sin i P-1
“Mass Function”: f(M) = P K3 / 2pG = Mx sin3(i) / (1 + Mc/Mx)2 < Mx
Techniques to infer i and estimate Mc/Mx (see references)  Mx
Compact Object Mass
Neutron Star Limit: 3 Mo
(dP/dr)0.5 < c
Rhoades & Ruffini 1974
Chitre & Hartle 1976
Kalogera & Baym 1996
Black Holes (BH)
Mx = 4-20 Mo
Neutron Stars (NS)
(X-ray & radio pulsars)
Mx ~ 1.4 Mo
Black Holes in the Milky Way
18 BHBs in Milky Way
16 fairly well
constrained 
(Jerry Orosz)
Scaled, tilted, and
colored for surface temp.
of companion star.
Identifications of X-ray Binaries
NS Binary: X-ray Bursts or Coherent X-ray Pulsations
NS Candidates: resemble NSBs in spectral & timing properties (limited info.)
BH Binary: Mass > 3 Mo from binary analyses ; no NS properties
BH Candidate: BHB X-ray properties + no pulsations + no X-ray bursts
Milky Way
LMC
nearby galaxies
Dynamical BHBs
18
2
3 (e.g., M33-X7)
BH Candidates
27
0
(? many ULXs)
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total
23
27 + ?
Transients
17
25 + ?
Accretion Disks and the Inner Disk Boundary
Keplerian orbits for accreting m
E(r)= U+K = 0.5 U(r) = -0.5 G Mx m r -1
Particle dE/dr = 0.5 G Mx m r -2
=
L(r) ~ d (dE/dr) = 0.5 e G Mx m r -2
dt
L(r) ~ 2p r dr sT4  T(r) ~ r -3/4
Real physical model (and MHD simulations):
• transport & conserve angular momentum; outflow?, rad. efficiency (e)
• 3-D geometry (disk thickness, hydrostatic eq., radiative transfer)
• B-fields and instabilities
• GR effects (Innermost Stable Circular Orbit, grav. redshift, beaming)
Accretion onto Compact Objects
Compact Object
Mo ; <Rkm>
GMmR-1 / mc2
Boundary Condition
0.4-1.3 ; 6000
10-4
crash on surface
neutron star 1.4-2.0 ; ~10
0.2
crash on surface
4-20 ; ~30a
~0.5
event horizon
~60a
~0.2
innermost stable
circular orbit (ISCO)
white dwarf
black hole
BH accretion disk
(a for 10Mo, a* = 0.5)
Milky Way Today: 108-109 BHs ; ~109 NSs ; > 1010 WDs
(Timmes, Woosley & Weaver 1996; Adams and Laughlin 1996)
Inner Disk Boundary for Accretion Disks
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Black Holes: Innermost Stable Circular Orbit (ISCO)
BH spin
0.0
0.5 0.75 0.9 0.98 1.0
----------------------------------------------------ISCO (Rg / GMx/c2): 6.0
4.2
3.2
2.3
1.6
1.0
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a*:
Neutron Stars
Inner Accretion Disk (? RNS < RISCO ?)
NS Surface  Boundary Layer (2nd heat source)
NS Spin (can influence bounday layer physics)
Magnetic Field Affects (Alfven Radius; control of inner accretion flow ;
accretion focus at polar cap  pulsars)
Black Hole X-ray Transient (or ‘X-ray Nova’)
GRO J1655-40
First known outbursts: 1994-95;
() 1996-97; 2005
Dynamical black hole binary
6.3 (+ 0.5) Mo
Relativistic Jets in 1994
~Radio-quiet, 1996-97, 2005
Black Hole X-ray Transient
GRO J1655-40
 Different X-ray States
Illustrating 3 BH States of Active Accretion
Energy spectra
Power density spectra
State
 steep power law
Energy (keV)
Frequency (Hz)
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thermal
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hard state
physical picture
Disk + ??
Illustrating 3 BH States of Active Accretion
Energy spectra
Power density spectra
State
 steep power law
Energy (keV)
Frequency (Hz)
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thermal

hard state
physical picture
Disk + ??
Time Series of Accretion States
GRO J1655-40
1996-97 outburst
Thermal x
Hard (jet)
g
Steep Power Law D
Intermediate
O
Time Series of Accretion States
XTEJ1550-564
Mx = 9.6 + 1.2 Mo
Thermal x
Hard (jet)
g
Steep Power Law D
Intermediate
O
Thermal State of Black Hole Binaries
1. Thermal State:
radiant heat of the inner accretion disk
disk fraction (2-20 keV) in energy spectrum:
power continuum (integrated 0.1-10 Hz):
no quasi-periodic oscillations (QPOs):
fdisk > 75% ;
rms < 0.075 ;
amax < 0.5%
Thermal State Paradigm
Theory: Hot gas in thin disk + viscous dissipation
Rel. MHD: Plasma + Magneto-Rotational Instability
 Thermal radiation ; weakly magnetized disk
Disk blackbody shape?
Disk blackbody energetics?
T(r) a r-p; p ~ 0.7 (Kubota et al 2005)
(GR tweak of p=0.75)
Kubota & Done 2004;
Gierlinski & Done 2004
Other Measures of Disk Structure
Disk Structure Changes in Other States?
GX339-4 Relativistic Fe line
e.g. Miller et al. 2004; but see Merloni & Fabian 2003
GR Applications for Thermal State
Emissivity vs. Radius in the Accretion Disk
Shakura & Sunyaev 1973; Makishima et al. 1986;
Page & Thorne 1974; Zhang, Cui, & Chen 1997
Gierlinski et al. 2001; Li et al. 2005
GR Applications for Thermal State
Relativistic Accretion Disk: Spectral Models
e.g. kerrbb in xspec
Li et al. 2005; Davis et al. 2005
• Integrate over disk and Bn(T)
• Correct for GR effects
(grav-z, Doppler, grav-focusing)
• Correct for radiative transfer
Thermal state  BH spin
Analyses of thermal state observations with
new GR-disk models  quantitative measures of a*
 Narayan Lecture (tomorrow)
Appendix: Tools for X-ray Data Analysis
Method
Application
Comments
Images
impulsive BJB jets
two cases (Chandra)
accretion disk
BH: infer a* if known Mx ; d
Spectrum
Model Continuum
Model Hard X-rays hot corona / Comptonization
two types: (1) jet ; (2) ???
Spectral Lines
BH: broad Fe K-a (6.4 keV)
corona fluoresces inner disk
emission profile  Mx ; a*
‘’
high-ioniz. absorption lines
seen in a few BHs
variable, magnetized disk?
‘’
redshifted absorption line
1 NS?: surface grav. redshift
Appendix: Tools for X-ray Data Analysis
Method
Application
Comments
Timing
Period Search
NS: X-ray Pulsars
several types; measure dP/dt
and pulse-profiles(E)
‘’
NS or BH binary orbits
wind-caused for HMXB
some LMXB eclipsers, dippers
‘’
Long-term Periods
precessing disks ;
? slow waves in dM/dt ?
Quasi-Period Oscillations BH and NS
low n (0.1-50 Hz)
high n (50-1300 Hz)
very slow (10-6 to 10-2 Hz)
rich in detail
common in some states
NS: var. n ; BH steady harmonics
some BH: disk instability cycles
Appendix: Tools for X-ray Data Analysis
Method
Application
Comments
Timing
Aperiodic Phenoma
‘’
Type I X-ray Bursts in NS
thermonucl. explosions on surface
ID as NS ; oscillations  spin ;
infer distance ; physical models improving
‘’
Type II X-ray Bursts
two NS cases ; cause ??
‘’
Superbursts (many hours)
C detonation in subsurface
? Probe NS interiors
‘’
Giant flares in Magnetars
? crust shifts + B reconnection
Progress?: coordinated timing / spectral analyses
References: Reviews
“Compact Stellar X-ray Sources”, eds. Lewin & van der Klis (2006) ;
16 chapters; some on ‘astro-ph’ preprint server: http://xxx.lanl.gov/form
Overview of Discovery
Rapid X-ray Variability
X-ray Bursts
Black Hole Binaries
Optical Observations
Isolated Neutron Stars
Jets
Accretion Theory
Magnetars
Psaltis
van der Klis
Strohmayer & Bildsten
McClintock & Remillard
Charles & Coe
Kaspi, Roberts, & Harding
Fender
King
Wood & Thompson
astro-ph/0410536
astro-ph/0410551
astro-ph/0301544
astro-ph/0306213
astro-ph/0308020
astro-ph/0402136
astro-ph/0303339
astro-ph/0301118
astro-ph/0406133
Other Reviews:
Narayan 2004, “Black Hole Event Horizon”, PThPS, 155, 263
Remillard & McClintock 2006, "X-Ray Properties of Black-Hole Binaries", ARAA, 44, 49
Done. Gierlinski, & Kubota 2007, “Modelling the behaviour of accretion flows in X-ray
binaries”, A&A Reviews, 15, 1
References
Other references.: Most are in ARAA, 44, 49 or in
McClintock & Remillard 2006 (previous slide)
Additional References:
Adams and Laughlin 1996, ApJ, 468, 576
Done & Gierlinski 2003, MNRAS, 342, 1041
Gierlinski & Done 2004, MNRAS, 347, 885
Kubota & Done 2004, MNRAS, 353, 980
Timmes, Woosley, & Weaver 1996, ApJ, 457, 834
Power Density Spectra and deadtime corrections:
Leahy et al. 1983, ApJ, 266, 160
Zhang et al. 1995, ApJ, 449, 930
Dennis Wei undergrad thesis (MIT; 2006): http://xte.mit.edu/~rr/dwei_thesis.pdf