Spatially resolved CIII]$\lambda$1909 emission in Haro 11
  The CIII]1909 (hereafter, C III]) line is the strongest ultraviolet emission
line after Ly$\alpha$ and is therefore of interest to high redshift studies of
star-forming (SF) galaxies near the epoch of reionization. It is thought that C
III] emission is strongest in galaxies with subsolar metallicity and low mass,
however, spectral observations of numerous such galaxies at high and low
redshift produce inconclusive or even contradictory results. We present the
first ever C III ] imaging, obtained with HST/STIS for the low-redshift SF
galaxy Haro 11. Cluster parameters like stellar mass, dust fraction and dust
attenuation, and ionization parameter, obtained through spectral energy
distribution fitting, show no correlation with the CIII] equivalent width (EW),
which may be due to a combination of the limitation of the models and the
age-homogeneity of the cluster population. Comparing the ratio of C III]
emission line flux from individual clusters to that of H$\alpha$, [O III], and
[O II] we find that the clusters with the highest EW(C III]) can be reconciled
only with Cloudy models with an extremely high C/O ratio of $\ge$
1.4(C/O)$_\odot$ for an ionizing population of single stars, binary stars, or a
mixture of binary stars and active galactic nuclei. Given the point-like nature
of strong C III], the integrated total strength of EW(C III]) becomes dependent
on the morphology of the galaxy, which would explain the large scatter in EW(C
III]) strengths, observed in galaxies with otherwise similar SF properties, and
of similarly low metallicity and stellar mass.
