**AAS 203rd Meeting, January 2004**

*Session 104 Black Holes*

Oral, Wednesday, January 7, 2004, 2:00-3:30pm, Centennial IV
[Previous] |
[Session 104] |
[Next]

## [104.06] The Origin of Supermassive Black Holes from Mestel Disks and the Rossby Instability

*S.A. Colgate (LANL), R. Cen (Princeton), H. Li, N. Currier, M.S. Warren (LANL)*

CHECKING The formation of supermassive black holes at the
centers of galaxies starts with inviscid gravitational
collapse forming a flat rotation curve, Mestel disk with
M_{<r} \propto r and \Sigma \propto 1/r . Such disks
should form from the collapse of any uniformly rotating,
isolated, gaseous cloud, either proto-galactic, galaxy-mass
damped Lyman-\alpha clouds or the gas which survives
galaxy mergers. In either case the disk will be unstable to
the Rossby vortex instability (RVI). This instability grows
from any large, steep pressure gradient in an optically
thick and geometrically thin disk. The non-linear vortices
initiated by the RVI can transport angular momentum with
transport length ~r far more efficiently than
turbulence with transport length, H << r, the disk
thickness. Compared to a viscosity-based Shakura-Sunyaev
disk the RVI transports angular momentum out to a much
larger radius, r ~10 pc in an L* galaxy, so more mass
is accreted into the central black hole. A typical galaxy
rotational velocity is v_{rot} = 200 km/s and the critical
column density (CCD) necessary to initiate the RVI is
\Sigma_{CCD} ~100 gm cm^{-2}. For M_{<r} = 2 \pi
r^{2} \Sigma we have r_{CCD} = v_{rot}^{2}/ ( 2 \pi
\Sigma_{CCD} G) , and the mass accreted becomes M_{BH} =
v_{rot}^{4}/(2 \pi \Sigma_{CCD} G^{2}) = 3 \times 10^{7}
M_{\odot}. Both the black hole mass M_{BH} and its
v_{rot}^{4} dependence are in good agreement with recent
observations, because v_{rot} = \sqrt 3 \; \sigma_{c}, where
\sigma_{c} is the velocity dispersion of the bulge at the
radius of mutual contact. (Supported by the DOE)

The author(s) of this abstract have provided an email address
for comments about the abstract:
colgate@lanl.gov

[Previous] |
[Session 104] |
[Next]

Bulletin of the American Astronomical Society, **35** #5

© 2003. The American Astronomical Soceity.