black holes in universe - from stellar masses to supramassive objects in galaxies
DESCRIPTION
Black Holes in Universe - From Stellar Masses to Supramassive Objects in Galaxies. Max Camenzind Center for Astronomy Heidelberg (ZAH) @ Landessternwarte (2005). Prologue: Chandrasekhar 1983. - PowerPoint PPT PresentationTRANSCRIPT
Black Holes in Universe -
From Stellar Masses to
Supramassive Objects in Galaxies
Max CamenzindCenter for Astronomy
Heidelberg (ZAH)@ Landessternwarte (2005)
Prologue: Chandrasekhar 1983• „The black holes of nature are the
most perfect macroscopic objects there are in the universe: the only elements in their construction are our concepts of space and time. And since the general theory of relativity provides only a single unique family of solutions for their descriptions, they are the simplest objects as well.“
No matter is involved in their construction [i.e. no EOS], a Black Hole is a global vacuum solution with horizon, a kind of gravitational soliton.
in Chandrasekhar (1983): „The Mathematical Theory of BHs“
Topics• The Long History of Black Hole Physics.• The Year 1963 and Kerr Black Hole
Gravitational field is not Newtonian ! • Evidence for the Existence of Black Holes
4 Classes of Astrophysical Objects. „No Hair Plane (Glatzenebene)“ (M,a).
• Accretion: New Paradigm of disk accretion onto Black Holes (Balbus & Hawley 1991).
• Magnetic Fields - The Spin Paradigm: The Ergosphere as a Source of Energy Launch Jets (Blandford & Znajek 1977) still largely not understood.
• Beyond Einstein ? Dreams and Future
The Long Way towards BHs
• 1915: Einstein postulates the field equations (together with Hilbert).
• 1916: Schwarzschild Solution Schwarzschild radius RS = 2GM/c² = 3 km M / MS
• Einstein denied the reality of Black Holes … He considered Black Holes as a mere mathematical curiosity.
• This view changed after his death detection of Quasars (> 1963) observation of Cygnus X-1 (1971)
1963 – Foundation of Black Holes
1923 - Milestone 1: George Birkhoff: Schwarzschild spacetime geometry is the unique spherically symmetric solution of the Einstein vacuum field equations
• 1939 - Robert Oppenheimer & Hartland Snyder show gravitational collapse of a pressureless homogeneous fluid sphere formation of a trapped region
• 1963 – Milestone 2: Roy Kerr solves the Einstein vacuum field equations for uncharged symmetric rotating systems
• 1963 – Milestone 3: Quasars are detected fuelled by accretion onto Black Holes
• 1965 - Ezra Newman and collaborators solve the Einstein-Maxwell equations for charged rotating systems
• 1967 - Werner Israel presents proof of a "no hair" theorem
1968 – 1977: Golden Age
• 1968 – Brandon Carter uses Hamilton-Jacobi theory to derive 1st-order equations of motion for particle moving in Kerr black holes Kerr Ray-Tracing
• 1969 - Roger Penrose discusses the Penrose process for the extraction of the spin energy from a Kerr black hole Free energy of BHs
• 1971 – Milestone 4: Identification of Cygnus X-1/HDE 226868 as a binary black hole candidate system.
• 1973 - David Robinson completes the proof of the uniqueness theorem for Kerr black holes
• 1977 – Milestone 5: Blandford-Znajek Process electromagnetic spin energy extraction from rotating black holes
• 1972 - Stephen Hawking proves that the area of a classical black hole's event horizon cannot decrease.
• 1972 - Jacob Bekenstein suggests that black holes have an entropy proportional to their surface area due to information loss effects
• 1973 - James Bardeen, Brandon Carter, and Stephen Hawking propose 4 laws of black hole mechanics in analogy with laws of thermodynamics Free energy
• 1973 - Stephen Hawking applies quantum field theory to black hole spacetimes and shows that black holes will radiate particles with a black-body spectrum which can cause black hole evaporation concept is important, but astrophysically not relevant, and still debated.
4 Laws of Black Hole Mechanics
• 1978 – Sargent et al. show evidence for a supermassive BH in the center of Messier 87 (“serious possibility”). This has been very much debated but confirmed !
• 1992 – Microquasar GRS 1915+105 found.• 1997 – Fe line redshifts of the innermost portions of
accretion disks around rotating supermassive black holes
• 2000 - Evidence for the hypothesis that Sagittarius A* is a supermassive black hole at the centre of the Milky Way galaxy
• 2002 – The most distant Black Hole found: Cosmological Redshift z = 6.43 ! (< 1 Gyear old)
• 2005 – BHs confirmed in ~ 20 X-Ray Binary Systems !• 2005 – BHs confirmed in ~ 30 nearby galactic centers !• 2005 – BHs found in ~ 100,000 Quasars !
1978 – 2005: Observations
The Year 1963 and the Physics of Kerr Black
Hole
How to Treat Gravity of BHs ?How to Treat Gravity of BHs ?
jdxidxij
dtidxi
dtii
ds 2)( 222
/n jj
t
In GR the spacetime is a differentiable manifold. The most natural thing is to to foliate it in t=const spatial hypersurfaces t.
function lapse::
Measures the “clocks ticking rates” on two t
vectorshifti ::
tensormetricij 3:: Measures distances among points on a t
unit timelike 4-vector normal to t
Measures the “stretching” of coordinates
t
1
4
6
2 Parameters:(i) Mass M(ii)Ang. Mom. a „Charge not relevant in Astrophysics“
Event HorizonrH = M + (M² - a²)1/2
Spacetime is stationary and axisymmetric
Source: Mass
Source: Ang. Mom.
Also for NSs !
Gravity Probe-Bwill confirm theExistence ofGravitomagnetism
4 Laws of BH Mechanics
Bekenstein 1973, Bardeen et al. 1973, Hawking 1974, 1975
Extracted bymagnetic effects
Blandford-Znajek Process
Blandford & Znajek (1977)
Load atinfinity
J
„Split-Monopole“ magnetospherecoupled to rotating Horizonwith Znajek Horizon bcdrives closed current system Subject of strong criticism (Punsley)
A Modern Version of BZ Mechanism
OLC: OuterLight Surface, compactfor Black HolesA: AlfvenSurface
Plasma injection fromnear ms orbit;Plasma accretioncausal: slow ms,Alfven and fastms points
Proto-Jet
CurrentSheet
wwwww
Magnetic fieldsadvected from„Infinity“
Twisting of Magnetic Fields
• Except for induction terms, evolution of toroidal magnetic field ~ Newtonian MHD
Source: Differential plasma rotation Schwarzschild: no shear ! Extreme Kerr: biggest effect !
T ~ RB
Operates outside horizon
Black Holes 2 Energy Reservoirs• Potential energy tapped by accretion X-rays• Rotational energy tapped by magnetic fields,
similar to rotating neutron stars (Blandford & Znajek 1977) will feed energy of JETS !
LLRotRot = E = ERotRot/t/tbrake brake
~ 10~ 104646 erg/s (M erg/s (MHH/10/1099 M MSS) (t) (tHH/t/tbrakebrake))
LLRotRot = E = ERotRot/t/tbrake brake
~ 10~ 103838 erg/s (M erg/s (MHH/10 M/10 MSS) (t) (tHH/t/tbrakebrake))ttbrake brake = f (a, B,…) [BZ 1977]= f (a, B,…) [BZ 1977]
LLBZBZ = k B = k BHH² r² rHH²c (a/M)² (²c (a/M)² (FF[[HH--FF]/]/HH²) ~ M²) ~ MHH
Anatomy of Black Holes
Black Hole Ergosphere Extended Boundary
Layer
For a > 0.7, radii move inside ergosphere
Each form of matterwill be driven to corotation
within the ergosphere ! Boundary Layer near Horizon ~ rH
In Schwarzschild:No rotation near Horizon !
H = (rH)
a = 0.5
a = 1.0
Outflowsin
Quasars & Micro-
Quasars ?
„StochasticFunnel-Flow“
Krolik 2005
DiskInflow
ConicalOutflow
Field Line Twisting by Rotating Black Holes
a = 0
a = 0.9
a = 0.5
a = .998
GRMHD Simulations (Hawley et al. 2005)
Astrophysical
Black Holesin the
Universe
Black Holes as Astrophysical Objects
• [ Primordial Black Holes: M < 2 MS]
• Stellar Black Holes: 2.2 MS < M < 100 MS
• Intermediate Mass Black Holes 100 MS < M < 105 MS (?)
• Supermassive Black Holes: 105 MS < M < 1010 MS reside in center of galaxies at all redshifts, 0 < z < 10 (?).
High-Mass XBCygnus X-1
Black Holes areformed in stellarCollapse >100.000 BHs in the Galaxy
1971 monitoredby UHURU
Cyg X-1 – Activity Cycles (VLA / RXTE)
When high in X-rays minimum in radio and vice versa Jet launch
Radio
X-Rays
HX
Low-MassX-Ray
Binaries
DIFFERENT BINARY SYSTEMS• type of the donor star type of accretion (wind or Roche lobe overflow)
• very different scales:
Every X-ray binary is a
possible microquasar!
J.A. Orosz
Stellar Mass Spectrum Clear Separation NSs vs BHs
NS
BHs
X-Ray Emission:VARIABILITY on all Time Scales
• Variations = changes in the state of the source
• lightcurves: GX 339-4 / GRS 1915+105
Variations on very different time scales !
“easy” observations for human time scale
X (2-10 keV)
Radio (2,25 GHz)
Rau et al (2003)
GX339-4 lightcurve
1996 2003GRS 1915+105
accretion / ejection coupling
• cycles of 30 minutes in GRS 1915+105 : ejections after an X-ray dip refilling of the internal part of the disc ? transient ejections during changes of states
same phenomenum in the quasar 3C 120 ? far slower !
Mirabel et al (1998)
Marscher et al (2002)
GRS 1915+105
Microquasar
SUPERLUMINAL EJECTIONS
• Move on the sky plane ~103 times faster• Jets are two-sided (allow to solve equations max. distance)
same Lorentz factor as in Quasars : ~ 5-10
Mirabel & Rodriguez (1994)
VLA at 3.5 cm
VLBI at 22 GHz ~ 1.3 cm
~ arcsec. scale ~ milliarcsec.
scale
QUASARS MICROQUASARS
Mirabel et al. 1992
Quasar 3C 223 Microquasar 1E1740.7-2942
radio (VLA) observations at 6 cm
VLA at 1477MHz ~ 20 cm
Black Holes in E-GalaxiesDrive Jets
Cygnus A (VLA)3C 219 (VLA)
Non-thermalRadio Plasma
--------- 100 kpc ------------
A. Müller (LSW) 2004
Black Hole Mass ~ Bulge Mass
for Inactive Galaxies30 NearbyGalaxies:
MH ~ 0.14% MB
MagorrianRelation
(N. Häring& H.-W. Rix:ApJL 2004)
Mass vs Luminosity of Quasars
LE = 2 x 1031 Watt x (M/MS) ~ 5 x 104 LS
maximumluminosityminimum mass for BHs
Black Hole „Two-Hair Plane“
RL Quasars,Radio Galaxies
BH sinGalacticCentersand QSOs
BH
s at High
R
edsh
ifts
Microq
uasars, S
tellar BH
s, M* >
30 In
termed
iate Mass
BH
s ???P
opu
lation III B
Hs
Neu
tron
Stars
Spin a of a Black Hole can bedetermined from Photon Propagation
Equations of geodesics integrable Carter Integrals
Imageof aRing
Line Emission from BH
Accretion
Schwarzschild Extreme Kerr
ExtremeRedshift
High-Redshift Quasars(SDSS)Form
inPrimordi
al Clusters
Very massive BHs
form very early !
Cosmic Quasar Population
H0 = 70 km/s/Mpc
k = 0.0
m = 0.3
= 0.7
QSO densitiesaugmented byfactor 3due to obscuration M. Camenzind 2005
Cosmic History & Black Holes
recombination
Cosmic Dark Age: no light no star, no quasar; IGM: HI
First light: the first galaxies and quasars in the universeEpoch of reionization: radiation from the first object lit up and ionize
IGM : HI HII reionization completed, the universe is transpartent and the dark ages ended
today
Credit: G. Fishman et al., BATSE, CGRO, NASA
BATSE GRB Final Sky Map: Astronomy Picture of the Day 2000 June 28
Gamma-Ray Burst Durations
Two Populations: Short – 0.03-3s Long – 3-1000sPossible third Population 1-10s
A Slow Explosion of massive star Formation of rotating BH with JETS long duration burst
Credit: Y. Grosdidier (U. Montreal) et al., WFPC2, HST, NASA
“Astronomy Picture of the Day: 2003 March 25”
On the Origin of Gold: Astronomy Picture of the Day: 2005 May 15
Merging of 2 neutron stars short bursts formation of a BH
New Paradigm for ADs:Disks are not viscous –Disks are turbulent -Turbulence driven by weak magnetic fields - Radiative MHD key vehicle[Balbus & Hawley 1991,98]
New Insight:Accretion is Turbulent
- not Viscous
New Paradigm:BHs in Different Accretion
States• BHs grow by accretion processes.• MHD turbulence drives angular
momentum transport in acretion disks (Balbus & Hawley magnetorotational instability, MRI). Disks are turbulent, not viscous !
• The well-known thin disk accretion model (Shakura & Sunyaev) only applies for high accretion rates, typically more than a few percent Eddington.
Truncated accretion at lower rates.
Two different accretion states depending on the accretion rate for given mass
Brinkmann& CamenzindLSW 2004
Esin et al. 1995A. Müller (LSW 2004)
Accretion Statesof Cyg X-1
High State (HS)[truncation radiusnear rms]Low State (LS)[truncation radiusmoves away]TransitionsEnergy emittedin Comptonizedphotons
What tell us X-rays?
MCG-6-30-15HST/WFPC-2
XMM-Newton 0.5-10keV light curve(Fabian et al. 2002)
Rapid X-ray variability of AGN strongly suggests X-rays come from innermost regions of accretion disk
GRMHD Accretion from a Torusas Initial Condition
Non-Radiative Accretion Flows
De Villiers, Hawley &Krolik 2003- 2005(3D non-conservativeGRMHD in BL);Gammie et al.2003, 2004(2D conservativeGRMHD in BL coordinates) Initial condition
(exact mech. equilibrium+ weak magnetic fields)
Initial State „Final State“
Meridional Planethrough a BHColour: Density
Torus+ weakmagnetic fields
TurbulentThick Disk Keplerian
Gammie et al. 2004
OutflowsFunnel
MagneticFields(originallyconfinedto torus)evolvetowardsa completelyturbulentstate.
Angularmomentum istransportedoutwards, someaccreted tospin up BH.
Fender 2004; Belloni 2005
When Plasma is included Ergospheric Jets ?
Beyond Einstein – The Observer‘s Dreams
2012 2020 2030Today
XMM
Planck
XEUS
NASA Homepage
XEUS - ESA
Beyond Einstein –
Heavy Numerical
Computations
Robust parallel GRMHD Codes
Beyond Einstein: Is there really a
Singularity in the Black Hole ?
Vacuum energy ispresent everywherein the Universe( Dark Energy)
Change theInterior of aBlack Hole
Regular state !
Mazur & Mottola 2001, 2004
Conclusions - Visions• Mass spectrum is continuous from stellar to 10
billion solar masses. Gap from 100 – 105 MS ?• But Kerr parameter a is not yet measurable !• GRMHD (> 2000) Plasma dynamics near BHs can
be successfully treated within Godunov schemes Use Kerr coordinates, bc within horizon ! MRI accretion theory is now tractable !
• Strong B-field limit (which is unphysical !): GR Magnetodynamics confirms BZ mechanism of energy extraction out of the ergosphere Jets are ergospheric plasma flows ?
• Weak field limit of GRMHD (relevant for MRI) is in unsatisfactory state, most results based on non-conservative methods Turbulent accretion to rotating BHs essentially unsolved, but now tractable with modern methods.
Also include radiation effects, which is important for high accretion rates at high z.