Which galaxy property is the best gauge of the oxygen abundance?

TL;DR

This study investigates which galaxy property best predicts oxygen abundance in star-forming galaxies, confirming stellar mass as the primary factor and showing other parameters have limited secondary influence.

Contribution

It provides a comprehensive analysis of 29 parameters affecting oxygen abundance, establishing stellar mass as the main predictor and identifying the functional form of the mass-metallicity relation.

Findings

Stellar mass is the best predictor of oxygen abundance.

The mass-metallicity relation is best described by a third-order polynomial.

Other parameters like gas fraction and star formation rate have limited secondary impact.

Abstract

We present an extensive exploration of the impact of 29 physical parameters in the oxygen abundance for a sample of 299 star-forming galaxies extracted from the extended CALIFA sample. We corroborate that the stellar mass is the physical parameter that better traces the observed oxygen abundance (i.e., the mass-metallicity relation, MZR), while other physical parameters could play a potential role in shaping this abundance, but with a lower significant impact. We find that the functional form that best describes the MZR is a third-order polynomial function. From the residuals between this best functional form and the MZR, we find that once considered the impact of the mass in the oxygen abundance, the other physical parameters do not play a significant secondary role in shaping the oxygen abundance in these galaxies (including the gas fraction or the star formation rate). Our analysis suggests that the origin of the MZR is related to the chemical enrichment evolution of the interstellar medium due, most likely, to the build-up of stellar mass in these star-forming galaxies.