Gravitation. Isaac Newton ( ) Johannes Kepler ( )

Transcription

1 Schwarze Löcher

2 History I

3 Gravitation Isaac Newton ( ) Johannes Kepler ( )

4 Isaac Newton ( ) Escape Velocity V = 2GM R 1/2 Earth: 11.2 km/s ( km/h) Moon: 2.3 km/s (8 300 km/h) Sun: 600 km/s ( km/h) A Treatise of the System of the World, London (1728)

5 The existence of dark stars (in Newtonian mechanics) (1783) V = 2GM R 1/2 John Michell ( ) (1799) Pierre-Simon Laplace ( )

6 History II & General Relativity

7 Albert Einstein ( ) Space ~ Time Energy = Matter Gravity = 4D Geometry SPECIAL Relativity (1905) Light velocity is constant in all reference frames Time and space are relative, moving clocks run slower, moving objects are shorter, c!300`000 km/s, equivalence principle: E = mc 2 GENERAL ERAL Relativity (1915) (Theory of Gravity) The basic idea is to drop Newton s idea of a mysterious force between masses and replace it with the 4-dimensional. Space-time is a dynamic entity, it is distorted by matter and it tells matter how to move. Pro ISSI, November 11, 2010

8 Gravity deforms space-time Gravitational Lensing (Einsteinkreuz)

9 K. Schwarzschild Finds black holes as a solution to Einstein s equations (1916) The event horizon R s = 2 M R. P. Kerr Finds the solution for rotating black holes (1963) J. A. Wheeler 1967 Black Holes Black Escape velocity c Hole singularity in space-time No Hair Theorem

10 Black Holes Regions of space from which nothing, not even light, can escape because gravity is so strong. Singularity Event horizon R 2GM/c 2 sch = U. Kraus Earth: R ~1 cm Sun: R~ 3 km

11 BH have NO HAIR J. A. Wheeler Black Hole

12 Birth of a Stellar-mass Black Hole

13 S. Chandrasekhar A massive star can collapse into something denser (1930) R. Oppenheimer & H. Snyder predict that massive stars can collapse into black holes (1939) M. Falanga

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15 1972 The First Black Hole?

16 X-ray Astronomy !! Bright X-ray emission!! Rapid X-ray variability

17 Optical Astronomy Sloan Digital Sky Survey!! 30 M " Blue supergiant main-sequence star (optically bright, X-ray dim)!! Orbits, 5.6 days, an unseen optically (but bright X-ray) object X-ray Binary System!! The companion has a mass between of ~ 10 M "

18 Cygnus X-1 What is it?!! A red giant would be easily seen!! A main-sequence star would be seen with a little effort!! Can t be a White Dwarf because M > 1.4 M "!! Can t be a Neutron star because M > 3 M " By elimination, we are left with a Black Hole

19 X-ray Binaries & X-ray Emission

20 Disk Accretion Shakura & Sunyaev, 1973, A&A Artist impression Energy released onto the Black Hole as X-ray Luminosity M G M NS L X! NS ~ erg s -1 R NS

21 Accretion disk model Shakura & Sunyaev, 1973, A&A

22 X-ray Emission

23 M Iron reflection line M

24 Black Hole Relativistic Emission lines

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27 Black Hole in our Galactic Center?

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29 Supermassive Black Hole in the Galaxy

30 NIR Evidences of a SM-BH at the GC NIR adaptive optics at VLT & Keck h! Proper motions of the stars of the central cluster h! Orbital parameters of the closest star S2 to the GC: P! 15.2 yr, V! 5000 km s -1 h! Dynamical center in Sgr A* h! Enclosed Dark Mass! M! within 124 AU = 17 l. h.! 2000 R S

31 L x L R correlation in accreting BH Sgr A* (Gallo et al. 03, Falcke et al. 04) 31

32 Types of Black Holes Stellar-mass" Must be at least 3 solar masses (~1031 kg) Intermediate mass! A few thousand to a few tens of thousands of solar masses; possibly the agglomeration of stellar mass holes Supermassive " Millions to billions of solar masses; located in the centers of galaxies We cannot see black holes directly, but their influence on the matter around them reveals their presence

33 X-ray Sources in the Galaxy observed with INTEGRAL Over 700 hard X-ray sources ranging from CV to AGN

34 Flares from our Galactic Center Black Hole

35 Astroteilchenphysik-Schule (Bag Schwarze Löcher: Kap 2 (Baganoff et al. Nature)

36 The geometry of the model B! Motion of Matter A (Time-like geodesics)! Curved photon trajectories (Null-like geodesics)! Doppler shift : (1 + z)! The solid angle : d" (R,d#,i,db) (Gravitational lensing effect)! Travel time delay! The observed flux! (F = $$$ I%d%d") 2007 March 21 36

37 Astroteilchenphysik-Schule Schwarze Löcher: Kap 2 (Falanga et al. 07, ApJ)

38 Astroteilchenphysik-Schule Schwarze Löcher: Kap 2 (Falanga et al. 07, ApJ)

39 Astroteilchenphysik-Schule Schwarze Löcher: Kap 2 (Falanga et al. 07, ApJ)

40 Black Holes are not quite black

41 Quantum gravity Considers quantum effects: quantum Black Holes are different from classical Black Holes (1974) S. Hawking (A Brief History of Time, 1988) Rotating black holes should create and emit particles. The Hawking radiation process reduces the mass of the black hole and is therefore also known as black hole evaporation.

42 Black Hole Evaporation Hawking-Strahlung Astroteilchenphysik-Schule Schwarze Löcher: Kap 1

43 Die Experimente am Large Hadron Collider bei Genf. Könnten kleine Schwarze Löcher für die Erde gefährlich werden?

44 (Falcke, Melia, Agol 2000, ApJL) The Shadow of a Black Hole It s getting closer! GR Model &0.6mm VLBI &1.3mm VLBI a=0.998 I = r -2 a = 0 I=const

45 Varying the Models Infall: a = i = 90º I = r -2 Jet: a = i = 90º I = hollow Infall: a = 0 i = 90º I = r -2 Jet: a = 0 i = 45º I = hollow Agol, Falcke, Melia, et al. (2001), conf. proc.