The HI column density distribution function in faint dwarf galaxies
  We present the HI column density distribution function,\fnh, as measured from
dwarf galaxies observed as part of the Faint Irregular Galaxy GMRT (FIGGS)
survey. We find that the shape of the dwarf galaxy \fnh\ is significantly
different from the \fnh\ for high redshift Damped \lya\ absorbers (DLAs) or the
\fnh\ for a representative sample of $z = 0$ gas rich galaxies. The dwarf \fnh\
falls much more steeply at high HI column densities as compared to the other
determinations. While $\sim 10%$ of the cross section above $\nh = 10^{20.3}
\acc$ at $z = 0$ is provided by dwarf galaxies, the fraction falls to $\lesssim
1%$ by $\nh \sim 10^{21.5} \acc.$ In the local universe, the contribution to
the high \nh\ end of the \fnh\ distribution comes predominantly from the
inclined disks of large galaxies. Dwarf galaxies, both because of their smaller
scale lengths, and their larger intrinsic axial ratios do not produce large HI
column densities even when viewed edge-on. If high column density DLAs/GRB
hosts correspond to galaxies like the local dwarfs, this would require either
that (i) the absorption arises from merging and not isolated systems or (ii)
the observed lines of sight are strongly biased towards high column density
regions.
