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Super Massive Black Holes Douglas Richstone University of Michigan - - PowerPoint PPT Presentation
Super Massive Black Holes Douglas Richstone University of Michigan - - PowerPoint PPT Presentation
Super Massive Black Holes Douglas Richstone University of Michigan Thanks to our sponsor M. Aller (UM) T. Lauer (NOAO) R. Bender (Munich) J. Kormendy (Texas) G. Bower (NOAO) J. Magorrian (C U) A. Dressler (OCIW)
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- M. Aller (UM)
- R. Bender (Munich)
- G. Bower (NOAO)
- A. Dressler (OCIW)
- S. Faber (UCSC)
- A. Filippenko (UCB)
- K. Gebhardt (Texas)
- R.Green (NOAO)
- L. Ho (OCIW)
- T. Lauer (NOAO)
- J. Kormendy (Texas)
- J. Magorrian (C U)
- J. Pinkney (Michigan)
- D. Richstone (Mich)
- C. Siopis (Mich)
- S. Tremaine
(Princeton)
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Summary
- Where does the “lore” come from
– Quasars, observations of test-mass dynamics, interpretation.
- The current demographic picture
– M-σ relation, bh mass spectrum, density, comparison to quasars.
- Emerging developments –
– Slouching toward a theory – The hunt for a “second parameter” – Extension to very low masses
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✷Where does the lore come from?
- “It’s idiocy to ignore the details.”
- Stanley Kunitz
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3c175
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Circular and parabolic orbits
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Orbit Superposition (Schwarzschild’s 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.
- I wish people wouldn’t call this 3 I- it is
any I!
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How well does the method work?
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✷ The current demographic picture
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Results of 15 year effort
- Most bulges have BH (97% so far).
- BH mass tracks main-body
parameters (L, sigma).
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- Bulge M/L ~ 3/10_h
- Density
- 2.5x10^5 Msun/Mpc_ for h=.65 (Yu &
Tremaine)
- 4.8x10^5h_ Msun/Mpc_ (Aller &
Richstone)
- consistent results from different
datasets.
- S = 2.2x10^5 Msun/Mpc3
- 6 – 9x10^5 (Fabian & Iwasa) qso+X-ray
background (and similar from Barger).
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BIG PROBLEM
The X-ray background energy exceeds the available sources of energy in known supermassive black holes. (the known population of SBH seems just adequate for the quasar energy).
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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).
- uqso ~ 10-4
- ρbh ~ uqsoε-1(1 - ε -gw – ejections)
- ρstars ~ 1
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Recent developments…
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- “Those who forget physics are doomed
to repeat it.”
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A taxonomy of theories for the M~v4 relation.
- The bh growth is limited by a mass budget
(Burkert & Silk).
- The bh growth is limited by a momentum
budget (Fabian)
- BH growth is limited by angular-momentum
(AGR).
- BH growth limited by energy conservation
(Silk & Rees, Blandford). Ciotti & Ostriker, pure core collapse).
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Pseudobulges:
… rapid rotation V that implies V/σ values well above the “oblate line” describing rotationally flattened, isotropic spheroids in the V/σ — ε diagram.
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COBE images show that our Galaxy’s bulge is boxy. We conclude that our Galaxy contains a pseudobulge.
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“We’re looking forward to looking backward”
- Alan Dressler
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Grav waves.
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Summary
- Supermassive black holes are here to
stay.
- Quasars are OK, may need some very
efficient emitters. X-ray background looks tough.
- M~v4 makes theorists salivate and may
lead to a model.
- Hints of a second parameter.