Explaining the observed velocity dispersion of dwarf galaxies by
  baryonic mass loss during the first collapse
  In the widely adopted LambdaCDM scenario for galaxy formation, dwarf galaxies
are the building blocks of larger galaxies. Since they formed at relatively
early epochs when the background density was relatively high, they are expected
to retain their integrity as satellite galaxies when they merge to form larger
entities. Although many dwarf spheroidal galaxies (dSphs) are found in the
galactic halo around the Milky Way, their phase space density (or velocity
dispersion) appears to be significantly smaller than that expected for
satellite dwarf galaxies in the LambdaCDM scenario. In order to account for
this discrepancy, we consider the possibility that they may have lost a
significant fraction of their baryonic matter content during the first infall
at the Hubble expansion turnaround. Such mass loss arises naturally due to the
feedback by relatively massive stars which formed in their centers briefly
before the maximum contraction. Through a series of N-body simulations, we show
that the timely loss of a significant fraction of the dSphs initial baryonic
matter content can have profound effects on their asymptotic half-mass radius,
velocity dispersion, phase-space density, and the mass fraction between
residual baryonic and dark matter.
