Supermassive Black Holes: The Inverse Dinosaur Problem Douglas Richstone University of Michigan

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Supermassive Black Holes The Inverse Dinosaur
Problem Douglas RichstoneUniversity of Michigan
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Summary

• The inverse dinosaur problem.
• Quasars, observations of test-mass dynamics,
  interpretation.
• The current demographic picture
• M-? relation, bh mass spectrum, density,
  comparison to quasars.
• Emerging developments
• a theory
• Extension to very low masses
• spins
• Possibility of gravitational wave observation of
  BH mergers.

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3c175
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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 1011 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.
• The decline of Quasars creates the inverse
  dinosaur problem where are the relics.

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Inverse dinosaur problem

• The light radiated by quasars is proportional to
  mc2 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 105 solar masses/Mpc3.
• Where are the relics?

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Circular and parabolic orbits
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M84
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Orbit Superposition (Schwarzschilds method)

• Assume a mass distribution.
• Compute the gravitational forces.
• Follow all the orbits.
• Sum the orbits to match the observed velocities.
• Failure rules out the mass distribution.

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NGC 4258

• NGC 4258 Maser mass is
• 3.9 107 at this distance.

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Results of 15 year effort

• Most bulges have BH (97 so far).
• BH mass tracks main-body parameters
• (L, ?).

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• Bulge M/L 3x10-3 h
• Density
• - 2.5x105 Msun/Mpc-3 for h.65 (Yu
  Tremaine)
• - 4.8x105h2 Msun/Mpc-3 (Aller Richstone)
• consistent results from different datasets.
• S 2.2x105 Msun/Mpc3

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A note on backgrounds

• Any background can be expressed in terms of the
  cosmic microwave background energy density
  (about 1eV/cm3).
• Backgrounds (other than the CMB) can be seen as
  integrals of source counts.
• uqso 10-4
• ?bh uqso?-1(1 - ?)(1 - fgw fejections)

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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 0.1m.c2 in 108yr
• Galaxy has stars 0.01Mc2 in 1010yr
• QSO light/starlight 103 m./M 1
• bh is as important as stars in early phases of
  galaxy.

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LISA sky
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Grav waves.