There has been a vast recent improvement in photometric and kinematic data for star clusters , Ultra Compact dwarfs , galactic nuclei , and local dSph galaxies , with Subaru contributing substantially to the photometric studies in particular .
These data show that there is a bimodal distribution in half-light radii , with stable star clusters always being smaller than 35pc , while stable galaxies are always larger than 120pc .
We extend the previously known observational relationships and interpret them in terms of a more fundamental pair of intrinsic properties of dark matter itself : dark matter forms cored mass distributions , with a core scale length of greater than about 100pc , and always has a maximum central mass density with a narrow range .
The dark matter in dSph galaxies appears to be clustered such that there is a mean volume mass density within the stellar distribution which has the very low value of about 0.1 M _ { \odot } pc ^ { -3 } .
None of the dSphs displays kinematics which require the presence of an inner cusp , while in two dSphs there is evidence that the density profile is shallow ( cored ) in the inner regions .
The maximum central dark matter density derived is model dependent , but is likely to have a mean value ( averaged over a volume of radius 10 pc ) of about 0.1 M _ { \odot } pc ^ { -3 } , which is 5GeV/c ^ { 2 } cm ^ { -3 } ) .
Galaxies are embedded in dark matter halos with these properties ; smaller systems containing dark matter are not observed .