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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 (ZAH) @ 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 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

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 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

7 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

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 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

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 ~ 10 46 erg/s (M H /10 9 M S ) (t H /t brake ) ~ 10 46 erg/s (M H /10 9 M S ) (t H /t brake ) L Rot = E Rot /t brake ~ 10 38 erg/s (M H /10 M S ) (t H /t brake ) ~ 10 38 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 < 10 10 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  >100.000 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 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 19962003 GRS 1915+105

38 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)

39 GRS 1915+105 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. 1992 Quasar 3C 223 Microquasar 1E1740.7-2942 radio (VLA) observations at 6 cm VLA at 1477MHz ~ 20 cm

42 GRS 1915+105 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  --------- 100 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 10 31 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 – 0.03-3s Long – 3-1000s 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. 1995 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-6-30-15 HST/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

71 GRMHD Accretion from a Torus as Initial Condition  Non-Radiative Accretion Flows De Villiers, Hawley & Krolik 2003 - 2005 (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. 2004 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 2012 2020 2030 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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