Detection of metallicity correlations in 100 nearby galaxies
  In this paper we analyse the statistics of the 2D gas-phase oxygen abundance
distributions of 100 nearby galaxies drawn from the Calar Alto Legacy Integral
Field spectroscopy Area survey. After removing the large-scale radial
metallicity gradient, we compute the two-point correlation functions of the
resulting metallicity fluctuation maps. We detect correlations in the majority
of our targets, which we show are significantly in excess of what is expected
due to beam-smearing, and are robust against the choice of metallicity
diagnostic. We show that the correlation functions are generally well-fit by
the predictions of a simple model for stochastic metal injection coupled with
diffusion, and from the model we show that, after accounting for the effects of
both beam smearing and noise, the galaxies in our sample have characteristic
correlation lengths of $\sim1$ kpc. Correlation lengths increase with both
stellar mass and star formation rate, but show no significant variation with
Hubble type, barredness, or merging state. We also find no evidence for a
theoretically-predicted relationship between gas velocity dispersion and
correlation length, though this may be due to the small dynamic range in gas
velocity dispersion across our sample. Our results suggest that measurements of
2D metallicity correlation functions can be a powerful tool for studying galaxy
evolution.
