SMP on SMBH

Are these two empirical laws similar? The same? Isothermal spheres Isothermal distribution functions Isothermal singular sphere Isothermal non-singular sphere Conclusions for the magnitude of dynamical friction in dark halos: the reason for efficient mergers Rotation and flattening of elliptical galaxies: only a weak

connection

Even the fantastic resolution ofthe VLBI radio interferometrycannot resolve the central engine.The dot in the lower left corner is of order 6 Schwarzschild radii,

i.e. several times the size of the black hole event horizon, from within which light or information cannot escape.

Empirical correlation exists between the supermassive black hole mass and the luminosity (and thus mass) of the bulge of the host galaxy, M87 isshown in a red circle

SMP on SMBHs

Tully-Fisher relationship, a correlation between the luminosityand rotation for diskgalaxies

Log

Vc

-2.5 log L

Faber-Jackson relationship:Luminosity ~ sigma^4 applies to ellipticals

Tully-Fisher relationshipLuminosity ~ (Vc)^3.85applies to disk galaxies

but the two are almost identical:both the disks and the ellipticalsare immersed in the same typeof dark halos which determinesthe maximum Vc via potentialwell depth.

(sorry, that’smy teenage daughter)

Good for modelingflat-Vc galaxiesin dark halos

...so this is one major reason why mergers of galactic systems areso rapid (a few to a few dozen periods)

One more empirical correlation: between rotation and flattening of ellipticals, which can be understood based on stellar dynamics

Fastest rotation according to theory

But remember: theory gives the upper envelope only. Most ellipticals are NOT supported or flattened by rotation. They simply are not relaxed; flatteningcomes from initial conditions, including geometry of encounter.