A constant dark matter halo surface density in galaxies

We confirm and extend the recent finding that the central surface density mu(0D) equivalent to r(00) of galaxy dark matter haloes, where r(0) and (0) are the halo core radius and central density, is nearly constant and independent of galaxy luminosity. Based on the co-added rotation curves (RCs) of similar to 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 log mu(0D) = 2.15 +/- 0.2 in units of log(M-circle dot pc(-2)). 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 mu(0D) is in sharp contrast to the systematical variations, by several orders of magnitude, of galaxy properties, including (0) and central stellar surface density