Metallicity correlations in galaxies

Abstract

Integrated field spectroscopy provides a unique window to gas-phase oxygen abundances in the interstellar medium of galaxies in both the local and high-redshift Universe. The two-point correlation function is a useful tool for extracting information from the 2D metallicity maps that integral field spectroscopy produces.

Using the current integrated field unit observations and simulations, this thesis tries to gradually investigate the following aspects. I show that two-point correlations of current observed metallicity maps can be described by a simple model that considers only stochastic metal injection and diffusion. The parameters extracted from fitting the data to this model are robust against observational effects and statistical choices. Correlation length, the characteristic turbulent diffusion length produced by the model, correlates with galaxy global properties, such as stellar mass and star formation rate. Further investigation on correlation lengths provide more information on the star formation duration and gas outflows in chemical evolution. With high resolution data it is also possible to begin measuring the characteristic sizes of the regions into which stellar sources initially inject their metals. Finally, I show that modern metal-tracing cosmological simulations can reproduce the correlation lengths seen in observations. Analysis of these simulations suggests that the correlation between correlation lengths and star formation rates does not evolve significantly over cosmic time, but that both quantities fluctuate over timescales of a few hundred Myr, with changes of the former preceding changes of the latter.

I conclude by suggesting avenues for future studies, including comparison between the two-point correlation functions of oxygen and nitrogen, extension to high-redshift metallicity distributions, and investigation of high spatial resolution simulations. Show more