The chemical case for no winds in dwarf irregular galaxies
  We argue that isolated gas-rich dwarf galaxies -- in particular, dwarf
irregular (dIrr) galaxies -- do not necessarily undergo significant gas loss.
Our aim is to investigate whether the observed properties of isolated, gas-rich
dwarf galaxies, not affected by external environmental processes, can be
reproduced by self-consistent chemo-photometric infall models with continuous
star formation histories and no mass or metals loss. The model is characterized
by the total mass of primordial gas available to the object, its characteristic
collapse timescale, and a constant star formation efficiency. A grid of 144
such models has been computed by varying these parameters, and their
predictions (elemental abundances, stellar and gas masses, photometric colors)
have been compared with a set of observations of dIrr galaxies obtained from
the literature. It is found that the models with moderate to low efficiency are
able to reproduce most of the observational data, including the relative
abundances of nitrogen and oxygen.
