Schwarze Löcher
History I
Gravitation Isaac Newton (1643-1727) Johannes Kepler (1571-1630)
Isaac Newton (1643-1727) Escape Velocity V = 2GM R 1/2 Earth: 11.2 km/s (40 320 km/h) Moon: 2.3 km/s (8 300 km/h) Sun: 600 km/s (2 160 000 km/h) A Treatise of the System of the World, London (1728)
The existence of dark stars (in Newtonian mechanics) (1783) V = 2GM R 1/2 John Michell (1724 1793) (1799) Pierre-Simon Laplace (1749 1827)
History II & General Relativity
Albert Einstein (1879 1955) 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
Gravity deforms space-time Gravitational Lensing (Einsteinkreuz)
K. Schwarzschild 1873-1916 Finds black holes as a solution to Einstein s equations (1916) The event horizon R s = 2 M R. P. Kerr 1934 - Finds the solution for rotating black holes (1963) J. A. Wheeler 1967 Black Holes 1911-2008 Black Escape velocity c Hole singularity in space-time No Hair Theorem
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
BH have NO HAIR J. A. Wheeler Black Hole
Birth of a Stellar-mass Black Hole
S. Chandrasekhar 1910-1995 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
1972 The First Black Hole?
X-ray Astronomy 1962 1972 1970!! Bright X-ray emission!! Rapid X-ray variability
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 "
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
X-ray Binaries & X-ray Emission
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 ~10 35-10 38 erg s -1 R NS
Accretion disk model Shakura & Sunyaev, 1973, A&A
X-ray Emission
M Iron reflection line M
Black Hole Relativistic Emission lines
Black Hole in our Galactic Center?
Supermassive Black Hole in the Galaxy
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! 3-4 10 6 M! within 124 AU = 17 l. h.! 2000 R S
L x L R correlation in accreting BH Sgr A* (Gallo et al. 03, Falcke et al. 04) 31
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
X-ray Sources in the Galaxy observed with INTEGRAL Over 700 hard X-ray sources ranging from CV to AGN
Flares from our Galactic Center Black Hole
7.10.2006 Astroteilchenphysik-Schule (Bag Schwarze Löcher: Kap 2 (Baganoff et al. Nature)
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
7.10.2006 Astroteilchenphysik-Schule Schwarze Löcher: Kap 2 (Falanga et al. 07, ApJ)
7.10.2006 Astroteilchenphysik-Schule Schwarze Löcher: Kap 2 (Falanga et al. 07, ApJ)
7.10.2006 Astroteilchenphysik-Schule Schwarze Löcher: Kap 2 (Falanga et al. 07, ApJ)
Black Holes are not quite black
Quantum gravity Considers quantum effects: quantum Black Holes are different from classical Black Holes (1974) S. Hawking 1942- (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.
Black Hole Evaporation Hawking-Strahlung 6.10.2006 Astroteilchenphysik-Schule Schwarze Löcher: Kap 1
Die Experimente am Large Hadron Collider bei Genf. Könnten kleine Schwarze Löcher für die Erde gefährlich werden?
(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
Varying the Models Infall: a = 0.998 i = 90º I = r -2 Jet: a = 0.998 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.