Galaxy Bulges As Tests of CDM vs MOND in Strong Gravity
arXiv:0802.1073 · doi:10.1086/591490
Abstract
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-variant versions of MOND, which can create the mirage of a Newtonian effective dark halo of density Pi r^{-1} near the center, where the characteristic surface density Pi=130alpha^{-1} Msun pc^{-2} and alpha is a fundamental constant of order unity fixed by the Lagrangian of the co-variant theory if neglecting environmental effects. We show with a toy analytical model and a hydrodynamical simulation that a constant background gravity due to MOND/TeVeS scalar field implies a critical pressure synchronizing starbursts and the formation of galaxy bulges and ellipticals. A universal threshold for the formation of the brightest regions of galaxies in a MONDian universe suggests that the central BHs, bulges and ellipticals would respect tight correlations like the M_{bulge}-M_{BH}-sigma relations. In general MOND tends to produce tight correlations in galaxy properties because its effective halo has less freedom and scatter than CDM halos.
30p, 6 figs, expanded. Accpeted for ApJ
References in corpus (20)
- Tidal dwarf galaxies as a test of fundamental physics
- Confrontation of MOND with the rotation curves of early-type disc galaxies
- Insight into the baryon-gravity relation in galaxies
- Velocity dispersion around ellipticals in MOND
- Milky Way potentials in CDM and MOND. Is the Large Magellanic Cloud on a bound orbit?
- Escaping from MOND
- A More Fundamental Plane
- Coincidences of Dark Energy with Dark Matter -- Clues for a Simple Alternative?
- Dynamical friction in modified Newtonian dynamics
- Loss of mass and stability of galaxies in MOND
- MOND plus classical neutrinos not enough for cluster lensing
- Forming Galaxies with MOND
- Evolution of spiral galaxies in modified gravity: II- Gas dynamics
- MOND and the lensing Fundamental Plane: No need for dark matter on galaxy scales
- Asymmetric Gravitational Lenses in TeVeS and Application to the Bullet Cluster
- The velocity distribution of SDSS satellites in MOND
- An analytic model for non-spherical lenses in covariant MOdified Newtonian Dynamics
- Strong lensing probability in TeVeS theory
- Self-consistent models of triaxial galaxies in MOND gravity
- Is Gravitational Lensing by Intercluster Filaments Always Negligible?