Galaxy And Mass Assembly (GAMA): The connection between metals, specific-SFR, and HI gas in galaxies: the Z-SSFR relation

TL;DR

This study investigates how gas metallicity, star formation rate, and neutral hydrogen content interrelate in galaxies of different masses, revealing that gas quantity influences galaxy evolution behaviors.

Contribution

It introduces a Z-SSFR relation model explaining how gas content causes opposite trends in metallicity and star formation across galaxy masses.

Findings

Gas amount correlates with metallicity and SSFR variations.

Low-mass galaxies with more gas have higher SSFR and lower metallicity.

Massive galaxies with more gas show moderate SSFR and high metallicity.

Abstract

We study the interplay between gas phase metallicity (Z), specific star formation rate (SSFR) and neutral hydrogen gas (HI) for galaxies of different stellar masses. Our study uses spectroscopic data from GAMA and SDSS star forming galaxies, as well as HI-detection from the ALFALFA and GASS public catalogues. We present a model based on the Z-SSFR relation that shows that at a given stellar mass, depending on the amount of gas, galaxies will follow opposite behaviours. Low-mass galaxies with a large amount of gas will show high SSFR and low metallicities, while low-mass galaxies with small amounts of gas will show lower SSFR and high metallicities. In contrast, massive galaxies with a large amount of gas will show moderate SSFR and high metallicities, while massive galaxies with small amounts of gas will show low SSFR and low metallicities. Using ALFALFA and GASS counterparts, we find that the amount of gas is related to those drastic differences in Z and SSFR for galaxies of a similar stellar mass.