What are we missing in elliptical galaxies ?
  The scaling relation for early type galaxies in the 6dF galaxy survey does
not have the velocity dispersion dependence expected from standard stellar
population models. As noted in recent work with SDSS, there seems to be an
additional dependence of mass to light ratio with velocity dispersion, possibly
due to a bottom heavy initial mass function. Here we offer a new understanding
of the 6dF galaxy survey 3D gaussian Fundamental Plane in terms of a
parameterized Jeans equation, but leave mass dependence of M/L and mass
dependence of structure still degenerate with just the present constraints.
Hybrid models have been proposed recently. Our new analysis brings into focus
promising lines of enquiry which could be pursued to lift this degeneracy,
including stellar atmospheres computation, kinematic probes of ellipticals at
large radius, and a large sample of one micron spectra.
