Dynamical effects of an extended cloud of Dark Matter on dwarf spheroidals

Abstract

If the dwarf spheroidals are embedded in an extended cloud of dark matter then their density profiles can be reproduced by assuming a Maxwellian distribution of velocities for the constituent stars. The observed luminosity profiles of dwarf spheroidals imply densities for the dark matter in the range 10^-26 to 10^-25 g cm^-3, and mass-to-luminosity ratios which are typically an order of magnitude greater than those of globular clusters. Neutrinos of mass ~10 eV and <v> ~1000 km s^-1 can provide this requisite density for the background.