Galaxy And Mass Assembly (GAMA): A deeper view of the mass, metallicity, and SFR relationships

TL;DR

This study investigates the complex relationships between gas metallicity, star-formation rate, and stellar mass in galaxies using SDSS and GAMA data, revealing evolution patterns and confirming a Fundamental Plane for star-forming galaxies.

Contribution

It combines SDSS and GAMA surveys to analyze galaxy parameter dependencies and proposes a simple model explaining different behaviors across galaxy masses.

Findings

Evidence for SFR and metallicity evolution up to z ~ 0.2

Strong correlations between SFR, Z, and stellar mass

Confirmation of a Fundamental Plane relating mass, metallicity, and SFR

Abstract

A full appreciation of the role played by gas metallicity (Z), star-formation rate (SFR), and stellar mass is fundamental to understanding how galaxies form and evolve. The connections between these three parameters at different redshifts significantly affect galaxy evolution, and thus provide important constraints for galaxy evolution models. Using data from the Sloan Digital Sky Survey-Data Release 7 (SDSS-DR7) and the Galaxy and Mass Assembly (GAMA) surveys we study the relationships and dependencies between SFR, Z, and stellar mass, as well as the Fundamental Plane for star-forming galaxies. We combine both surveys using volume-limited samples up to a redshift of z ~ 0.36. The GAMA and SDSS surveys complement each other when analyzing the relationships between SFR, Mass and Z. We present evidence for SFR and metallicity evolution to z ~ 0.2. We study the dependencies between SFR, Mass, Z, and specific star-formation rate (SSFR) on the M-Z, M-SFR, M-SSFR, Z-SFR, and Z-SSFR relations, finding strong correlations between all. Based on those dependencies, we propose a simple model that allows us to explain the different behaviour observed between low and high mass galaxies. Finally, our analysis allows us to confirm the existence of a Fundamental Plane, for which Mass=f(Z, SFR) in star-forming galaxies.