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Black Holes in Universe - From Stellar Masses to Supramassive Objects in Galaxies Max Camenzind Center for Astronomy Heidelberg Landessternwarte.

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Presentation on theme: "Black Holes in Universe - From Stellar Masses to Supramassive Objects in Galaxies Max Camenzind Center for Astronomy Heidelberg Landessternwarte."— Presentation transcript:

1 Black Holes in Universe - From Stellar Masses to Supramassive Objects in Galaxies Max Camenzind Center for Astronomy Heidelberg Landessternwarte (2005)

2 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“

3 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

4 The Long Way towards BHs 1915: Einstein postulates the field equations (together with Hilbert). 1916: Schwarzschild Solution  Schwarzschild radius R S = 2GM/c² = 3 km M / M S 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)

5 1963 – Foundation of Black Holes Milestone 1: George Birkhoff: Schwarzschild spacetime geometry is the unique spherically symmetric solution of the Einstein vacuum field equations 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 Ezra Newman and collaborators solve the Einstein-Maxwell equations for charged rotating systems Werner Israel presents proof of a "no hair" theorem

6 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 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 as a binary black hole candidate system 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

7 Stephen Hawking proves that the area of a classical black hole's event horizon cannot decrease Jacob Bekenstein suggests that black holes have an entropy proportional to their surface area due to information loss effects James Bardeen, Brandon Carter, and Stephen Hawking propose 4 laws of black hole mechanics in analogy with laws of thermodynamics  Free energy 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

8 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 found – Fe line redshifts of the innermost portions of accretion disks around rotating supermassive black holes 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

9 The Year 1963 and the Physics of Kerr Black Hole

10 How to Treat Gravity of BHs ? In GR the spacetime is a differentiable manifold. The most natural thing is to to foliate it in t=const spatial hypersurfaces  t. Measures the “clocks ticking rates” on two  t Measures distances among points on a  t unit timelike 4-vector normal to  t Measures the “stretching” of coordinates tt 1 4 6

11 2 Parameters: (i)Mass M (ii)Ang. Mom. a „Charge not relevant in Astrophysics“  Event Horizon r H = M + (M² - a²) 1/2 Spacetime is stationary and axisymmetric

12 Source: Mass Source: Ang. Mom. Also for NSs !

13 Gravity Probe-B will confirm the Existence of Gravitomagnetism

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16 4 Laws of BH Mechanics Bekenstein 1973, Bardeen et al. 1973, Hawking 1974, 1975

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19 Extracted by magnetic effects

20 Blandford-Znajek Process Blandford & Znajek (1977) Load at infinity J „Split-Monopole“ magnetosphere coupled to rotating Horizon with Znajek Horizon bc drives closed current system  Subject of strong criticism (Punsley)

21 A Modern Version of BZ Mechanism OLC: Outer Light Surface, compact for Black Holes A: Alfven Surface Plasma injection from near ms orbit; Plasma accretion causal: slow ms, Alfven and fast ms points Proto-Jet Current Sheet wwwww Magnetic fields advected from „Infinity“

22 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

23 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 ! L Rot = E Rot /t brake ~ erg/s (M H /10 9 M S ) (t H /t brake ) ~ erg/s (M H /10 9 M S ) (t H /t brake ) L Rot = E Rot /t brake ~ erg/s (M H /10 M S ) (t H /t brake ) ~ erg/s (M H /10 M S ) (t H /t brake ) t brake = f (a, B,…) [BZ 1977] L BZ = k B H ² r H ²c (a/M)² (  F [  H -  F ]/  H ²) ~ M H

24 Anatomy of Black Holes

25 Black Hole Ergosphere  Extended Boundary Layer For a > 0.7, radii move inside ergosphere

26 Each form of matter will be driven to corotation within the ergosphere !  Boundary Layer near Horizon ~ r H In Schwarzschild:  No rotation near Horizon !  H =  (r H )

27 a = 0.5 a = 1.0

28 Outflows in Quasars & Micro- Quasars ?  „Stochastic Funnel- Flow“ Krolik 2005 Disk Inflow Conical Outflow

29 Field Line Twisting by Rotating Black Holes a = 0 a = 0.9 a = 0.5 a =.998 GRMHD Simulations (Hawley et al. 2005)

30 Astrophysical Black Holes in the Universe

31 Black Holes as Astrophysical Objects [ Primordial Black Holes: M < 2 M S ] Stellar Black Holes: 2.2 M S < M < 100 M S Intermediate Mass Black Holes 100 M S < M < 10 5 M S (?) Supermassive Black Holes: 10 5 M S < M < M S  reside in center of galaxies at all redshifts, 0 < z < 10 (?).

32 High-Mass XB Cygnus X-1 Black Holes are formed in stellar Collapse  > BHs in the Galaxy 1971 monitored by UHURU

33 Cyg X-1 – Activity Cycles (VLA / RXTE) When high in X-rays  minimum in radio and vice versa  Jet launch Radio X-Rays HX

34 Low-Mass X-Ray Binaries

35 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

36 Stellar Mass Spectrum  Clear Separation NSs vs BHs NS BHs

37 X-Ray Emission: VARIABILITY on all Time Scales Variations = changes in the state of the source lightcurves: GX / GRS  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 GRS

38 accretion / ejection coupling cycles of 30 minutes in GRS :  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)

39 GRS Microquasar

40 SUPERLUMINAL EJECTIONS Move on the sky plane ~10 3 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

41 QUASARS  MICROQUASARS Mirabel et al Quasar 3C 223 Microquasar 1E radio (VLA) observations at 6 cm VLA at 1477MHz ~ 20 cm

42 GRS Disk Evolution

43 Spectrum of a Microquasar If jet emission extends up to the visible band, the jet has > 10% of the total power Markoff et al. (2001) If jet emission dominates the X-ray band, the jet has > 90% of the total power Synchrotron (jet) thermal (disc) ? MeV emission due to Synch. Self-Compton from the compact jet ? GeV ? (GLAST) shocks with the ISM  TeV ?

44 Quasars 3C 273

45 Spectrum of a Quasar Synchrotron (jet) thermal (disk) inverse Compton (jet) Lichti et al. (1994) Jets are the only truly broad-band sources in the universe (radio-TeV)!

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47 Black Holes in E-Galaxies Drive Jets Cygnus A (VLA) 3C 219 (VLA) Non-thermal Radio Plasma  kpc 

48 Quasar Spectra

49 A. Müller (LSW) 2004

50 Black Hole Mass ~ Bulge Mass for Inactive Galaxies 30 Nearby Galaxies: M H ~ 0.14% M B Magorrian Relation (N. Häring & H.-W. Rix: ApJL 2004)

51 Mass vs Luminosity of Quasars L E = 2 x Watt x (M/M S ) ~ 5 x 10 4 L S maximum luminosity  minimum mass for BHs

52 Black Hole „Two-Hair Plane“ RL Quasars, Radio Galaxies BH s in Galactic Centers and QSOs BHs at High Redshifts Microquasars, Stellar BHs, M * > 30 Intermediate Mass BHs ???Population III BHs Neutron Stars

53 Spin a of a Black Hole can be determined from Photon Propagation Equations of geodesics integrable  Carter Integrals

54 Image of a Ring

55 Line Emission from BH Accretion

56 Schwarzschild Extreme Kerr Extreme Redshift

57 High- Redshift Quasars (SDSS) Form in Primordial Clusters Very massive BHs form very early !

58 Cosmic Quasar Population H 0 = 70 km/s/Mpc  k = 0.0  m = 0.3    = 0.7 QSO densities augmented by factor 3 due to obscuration M. Camenzind 2005

59 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 universe  Epoch 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

60 Credit: G. Fishman et al., BATSE, CGRO, NASA BATSE GRB Final Sky Map: Astronomy Picture of the Day 2000 June 28

61 Gamma-Ray Burst Durations Two Populations: Short – s Long – s Possible third Population 1-10s

62 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”

63 On the Origin of Gold: Astronomy Picture of the Day: 2005 May 15 Merging of 2 neutron stars  short bursts  formation of a BH

64 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

65 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.

66  Two different accretion states depending on the accretion rate for given mass

67 Brinkmann & Camenzind LSW 2004

68 Esin et al A. Müller (LSW 2004)

69 Accretion States of Cyg X-1 High State (HS) [truncation radius near rms] Low State (LS) [truncation radius moves away] Transitions  Energy emitted in Comptonized photons

70 What tell us X-rays? MCG HST/WFPC-2 XMM-Newton keV light curve (Fabian et al. 2002) Rapid X-ray variability of AGN strongly suggests X-rays come from innermost regions of accretion disk

71 GRMHD Accretion from a Torus as Initial Condition  Non-Radiative Accretion Flows De Villiers, Hawley & Krolik (3D non-conservative GRMHD in BL); Gammie et al. 2003, 2004 (2D conservative GRMHD in BL coordinates) Initial condition (exact mech. equilibrium + weak magnetic fields)

72 Initial State „Final State“ Meridional Plane through a BH Colour: Density Torus + weak magnetic fields Turbulent Thick Disk  Keplerian Gammie et al Outflows Funnel

73 Magnetic Fields (originally confined to torus) evolve towards a completely turbulent state.  Angular momentum is transported outwards, some accreted to spin up BH.

74 Fender 2004; Belloni 2005

75 When Plasma is included  Ergospheric Jets ?

76 Beyond Einstein – The Observer‘s Dreams Today XMM Planck XEUS NASA Homepage

77 XEUS - ESA

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79 Beyond Einstein – Heavy Numerical Computations Robust parallel GRMHD Codes

80 Beyond Einstein: Is there really a Singularity in the Black Hole ? Vacuum energy is present everywhere in the Universe (  Dark Energy)  Change the Interior of a Black Hole  Regular state ! Mazur & Mottola 2001, 2004

81 Mottola-Mazur Gravastar  5 Layers External Schwarzschild vacuum, r>2M Thin shell at r > 2M, surface density  + and surface tension. [ Finite-thickness shell at r = 2M, stiff matter. ] [ Second thin shell at r < 2M, surface density  -, surface tension. ] de Sitter vacuum inside: P = -  c²  bulk of mass  no singularity r=0

82 Conclusions - Visions Mass spectrum is continuous from stellar to 10 billion solar masses. Gap from 100 – 10 5 M S ? 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.


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