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Published byPatrick Todd Modified over 8 years ago
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Black Holes and the Evolution of Galaxies…
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Summary Quasars and Evolution: the universe becomes interesting How we do it: things invisible to see. Demographics: the inverse dinosaur problem. –M- relation, bh mass spectrum. Emerging developments – –The energy budget for galaxy formation –Extension to very low masses –spins –Possibility of gravitational wave observation of BH mergers.
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In 1963 the universe became more interesting Quasars Evolution The initial conditions
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3c175
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Universe baby picture: WMAP 5 year image.
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Mysterious properties of quasistellar objects Rapid variability – minutes. –Light travel time across inner solar system. Directed energy output (collimated beams of high-energy particles. “Superluminal” motion. Enormous luminosities ~ 10 11 suns. Objects the size of the solar system that outshine the galaxy. Quasars were populous in the youthful universe, but are rare now.
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Quasars and Black Holes Small size, large luminosity and apparent stability suggest that quasars are gravity powered. Ultimate gravitational engine is a bh. Some fraction of accreted energy is radiated (can greatly exceed thermonuclear energy). BH turns off when fuel is cut off.
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Inverse dinosaur problem The light radiated by quasars is proportional to mc 2 of accreted matter. The mass of order m of the accreted matter. The density of quasars mandates a density of bh of about 2 x 10 5 solar masses/Mpc 3. Where are the relics?
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Cavendish experiment
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M84
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Orbit Superposition (Schwarzschild’s method) Assume a mass distribution (light + BH). Compute the gravitational forces. Follow all the orbits. Sum the orbits to match the observed light distribution and velocities. Failure rules out the mass distribution.
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Results of 20 year effort Most bulges have BH (97% so far). BH mass tracks main-body parameters (L, ).
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Gultekin et al.
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Aller & Richstone
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Bulge M/L ~ 3x10 -3 h Density - 2.5x10 5 Msun/Mpc -3 for h=.65 (Yu & Tremaine) - 4.8x10 5 h 2 Msun/Mpc -3 (Aller & Richstone) -consistent results from different datasets. -S = 2.2x10 5 M sun /Mpc 3
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Only gas will produce the correct Soltan number Accreting matter: –Stars –Degenerate objects –Dark matter –Gas
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Implications BH growth spurt during quasar era (is this the epoch of bulge formation?). –What is the pedigree of BH and galaxies? Co-Evolution! --- feeding, bar disruption, core scouring, mergers --- bh growh connected to galaxy evolution. Is any of this observable?
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Thermodynamics of the protogalaxy QSO emits Xrays: 0.1*m.c 2 in 10 8 yr Galaxy has stars: 0.01*Mc 2 in 10 10 yr QSO light/starlight ~ 10 3 m./M ~ 1 bh is as important as stars in early phases of galaxy. Some fraction of BH luminosity is mechanical - may be sufficient to blow gas out of galaxy.
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