Galaxy Bulges As Tests of CDM vs MOND in Strong Gravity

The tight correlation between galaxy bulges and their central black hole masses likely emerges in a phase of rapid collapse and starburst at high redshift, due to the balance of gravity on gas with the feedback force from starbursts and the wind from the black hole; the average gravity on per unit mass of gas is ~ 2 x 10^-10 m/sec^2 during the star burst phase. This level of gravity could come from the real r^{-1} cusps of Cold Dark Matter (CDM) halos, but the predicted gravity would have a large scatter due to dependence on cosmological parameters and formation histories. Better agreement is found with the gravity from the scalar field in some co-varia

How to form bulges/ellipticals in dark halos as fast as central black holes?

Gravity is nearly a universal constant in the cusp of an NFW galaxy halo. Inside this external field an isothermal gas sphere will collapse and trigger a starburst if above a critical central pressure. Thus formed spheroidal stellar systems have Sersic-profile and satisfy the Faber-Jackson relation. The process is consistent with observed starbursts. We also recover the M_BH vs. velocity dispersion relation, if the gas collapse is regulated or resisted by the feedback from radiation from the central BH.

A feedback compression star formation model and the black hole - bulge relations

We present a feedback compression model to describe the galactic spheroid formation and its relation with the central nuclear activity. We suggest that the star formation itself can serve as the positive feedback in some extremely dense region to trigger the starburst. The star formation rate as well as the related stellar feedback-induced turbulence will be maximized under the regulation of the background dark halos gravity. There is also stellar feedback acting inward to confine and obscure the central black hole (BH) till the BH grows sufficiently large to satisfy a balance condition between the accretion disk wind and the inward stellar feedback. The extremely vigorous star formation activity, the BH - bulge relations, the maximum velocity dispersion as well as the maximum BH mass are investigated based on such scenario, and are found to be consistent with observations.