Role of galactic gaseous halos in recycling enriched winds from bulges
  to disks: A new bulge-disk chemical connection
  We demonstrate for the first time that gaseous halos of disk galaxies can
play a vital role in recycling metal-rich gas ejected from the bulges and thus
in promoting chemical evolution of disks. Our numerical simulations show that
metal-rich stellar winds from bulges in disk galaxies can be accreted onto the
thin disks owing to hydrodynamical interaction between the gaseous ejecta and
the gaseous halos, if the mean densities of the halos (rho_ hg) are as high as
10^{-5} cm^{-3}. The total amount of gas that is ejected from a bulge through a
stellar wind and then accreted onto the disk depends mainly on rho_ hg and the
initial velocity of the stellar wind. About ~ 1% of gaseous ejecta from bulges
in disk galaxies of scale length a_d can be accreted onto disks around R ~ 2.5
a_ d for a reasonable set of model parameters. We discuss these results in the
context of the origin of the surprisingly high metallicities of the solar
neighborhood disk stars in the Galaxy. We also discuss some implications of the
present results in terms of chemical evolution of disk galaxies with possibly
different rho_ hg in different galaxy environments.
