1 / 38

by Paola Rebusco

Black Holes Spin!. by Paola Rebusco. MIT, April 22nd 2009. BH have NO HAIR. By J.A. Wheeler. Black Holes’ Anatomy. Once they form they are left with ……… Mass Spin Charge. km. miles. Some History.

ashley
Télécharger la présentation

by Paola Rebusco

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Black Holes Spin! by Paola Rebusco MIT, April 22nd 2009

  2. BH have NO HAIR By J.A. Wheeler

  3. Black Holes’ Anatomy Once they form they are left with ……… Mass Spin Charge km miles

  4. Some History John Michell (1784) and Pierre-Simon Laplace (1796) propose the existence of “dark stars”…that lock in light (in Newtonian mechanics) Albert Einstein publishes his first paper on GR (1915) Karl Schwarzschild finds black holes as a solution to Einstein’s equations (1916) Subrahmanyan Chandrasekhar suggests that a massive star can collapse into something denser (1930) Robert Oppenheimer and Hartland Snyder predict that massive stars can collapse into black holes (1939) Roy Kerr finds the solution for rotating black holes (1963) Stephen Hawking considers quantum effects: quantum black holes are different from classical black holes (1974)

  5. THROUGH the ample open door of the peaceful country barn, A sun-lit pasture field, with cattle and horses feeding; And haze, and vista, and the far horizonS, fading away.. AFarm-Picture Walt Whitman - Leaves of Grass 1900

  6. region http://nrumiano.free.fr/Images/tn_kerr_E.gif

  7. Frame-dragging TEST: Gravity Probe B

  8. Black Holes in Theory can have any Sizes!

  9. QUIZ What would happen to the Earth’s orbit IF the Sun was to be replaced by a black hole of the same mass and spin?

  10. IF black holes exist… how do they form?!

  11. REMEMBER: gravity against pressure gradient • High Temperature and Pressure: successive fusion reactions! Life Cycle of Massive Stars Fusing H into He, He into C,O, …and so on into Fe Carbon Burning Oxygen Burning

  12. Iron is the most stable… Supernovae Type II and Hypernovae! • Collapse..250000000 km/h! • More energy released than our Sun in billions of years! What is left?

  13. Death of a Star - Birth of a Black Hole

  14. Do Black Holes in The Universe Spin?!

  15. YEAH! a=0.75-0.90 (Gammie et al 2004)

  16. Mergers! Short Gamma Ray Bursts NOTE: spin up

  17. INTERMEZZO: Quantum or Not Quantum? Any black hole emits Hawking black body radiation with The characteristic time for quantum effectsis For MBH= 1 MSUN ….

  18. QUIZ The energy reached by the Large Hadron Collider MAY produce micro black holes ( )…if this were to occur, would it be dangerous?Why?

  19. Commercial Break!!!(Further Reading) • Schutz, B. A First Course in General Relativity • Carroll, S. An Introduction to General Relativity: Spacetime and Geometry • D’Inverno, R. Introducing Einstein's Relativity • Wald, Robert. General Relativity • Hartle J. An Introduction to Einstein’s General Relativity • Thorne, K. Black Holes and Time Warps: Einstein's Outrageous Legacy • Begelman M. & Rees M. Gravity’s Fatal Attraction: BH in the Universe • Ferguson K. Prisons of Light -Black Holes

  20. Do Black Holes Exist? • Lasciate ogni speranza, • o voi ch’entrate. • Abandon all hope, • you who enter here. • Dante Alighieri • (Divina Commedia-Hell) Artist impression John Wheeler 1967- Physics Today

  21. Black Holes are not Alone! Binaries (BH+Companion) Live in Galaxies Affect the Motion of Stars

  22. X-ray Binaries Artist impression

  23. Shakura & Sunyaev model (1973) Thin disks: • h/r<<<1 neglect higher order terms • l=lk, : keplerian angular momentum • Viscosity prescription - (molecular viscosity is not enough)

  24. 1972: Cygnus X-1 • The first black hole candidate!!!!!!! • A blue supergiant (optically bright, X-ray dim) orbits an unseen (optically, but bright X-ray) companion! • Rapid X-ray variability

  25. Some X-ray Telescopes RXTE Timing XMM Newton Spectroscopy Chandra Imaging

  26. www.jwst.nasa.gov/ comparison.htm

  27. Radio Galaxies (A type of galaxy with an Active Galactic Nucleus=AGN) • fast (less than 1 yr) change in time • A lot of power in a small space • - Superluminal jets!

  28. Supermassive Black Holes powering AGN!!! NGC 1275 is very active… (radio,X,GAMMA) (Credit: Radio: NRAO/AUI/NSF)

  29. In our Galactic Center…

  30. ..or quiet : Sagittarius A* Infrared Observation 1 light year = 9.4605284 1015 m

  31. What do Accretion and BH Spin have in common?

  32. Where the disk ‘ends’…. ISCO (depends on the spin)

  33. (Miller et al 09)

  34. Spin Measurements • Relativistic Lines - • Relativistic Doppler Shift • and gravitational red shift • STRONGEST at the ISCO • Accretion disk continuum - • Closer is hotter (Miller et al 09)

  35. Spin Measurements • Quasi Periodic Oscillations - • Lie in the range • of ORBITAL FREQUENCIES • of geodesics close to the • ISCO • Reverberation (measure time lags between variations in the continuum and in emission lines) • Polarimetry (the rotation angle is energy -> radius dependent) Courtesy of R.Remillard

  36. Other (many) challenges! Gravitational Waves- Galaxy-Black Holes growth Ligo-Lisa-Virgo-…

  37. Other (many) challenges! Test GR What happens at the singularity? Understand Quantum Gravity!!!!!

  38. DO YOU HAVE ANY QUESTIONS? ALL THE ANSWERS? SEND A MAIL TO:pao AT space.mit.eduOR PASS BY:BLDG 37, Office 675

More Related