2009MNRAS.397.1169D

We confirm and extend the recent finding that the central surface density µ_0D≡ r₀ρ₀ of galaxy dark matter haloes, where r₀ and ρ₀are the halo core radius and central density, is nearly constant and independent of galaxy luminosity. Based on the co-added rotation curves (RCs) of ∼1000 spiral galaxies, the mass models of individual dwarf irregular and spiral galaxies of late and early types with high-quality RCs, and the galaxy-galaxy weak-lensing signals from a sample of spiral and elliptical galaxies, we find that logµ_0D= 2.15±0.2 in units of log(M_☉/pc2). We also show that the observed kinematics of Local Group dwarf spheroidal galaxies are consistent with this value. Our results are obtained for galactic systems spanning over 14 mag, belonging to different Hubble types and whose mass profiles have been determined by several independent methods. In the same objects, the approximate constancy of µ_0D is in sharp contrast to the systematical variations, by several orders of magnitude, of galaxy properties, including ρ₀ and central stellar surface density.