Minimum mass of galaxies from BEC or scalar field dark matter

Abstract

Many problems of cold dark matter models such as the cusp problem and the missing satellite problem can be alleviated, if galactic halo dark matter particles are ultra-light scalar particles and in Bose-Einstein condensate (BEC), thanks to a characteristic length scale of the particles. We show that this finite length scale of the dark matter can also explain the recently observed common central mass of the Milky Way satellites ($\sim 10^7 M_\odot$) independent of their luminosity, if the mass of the dark matter particle is about $10^{-22} eV$.