Different behaviour of the gas-phase and stellar metallicity in the central part of MaNGA galaxies

TL;DR

This study analyzes the differences between gas-phase and stellar metallicity in MaNGA galaxies, revealing that massive galaxies often have lower gas metallicity in their centers, likely due to internal gas flows or accretion processes.

Contribution

It provides a detailed comparison of gas and stellar metallicities across galaxy masses and suggests internal processes influence central gas metallicity disparities.

Findings

Gas metallicity aligns with stellar metallicity in intermediate-mass galaxy centers.

Massive galaxies show a significant negative disparity in central metallicity.

Reduced gas-phase metallicity in massive red galaxies correlates with low star formation rates.

Abstract

We quantified the disparity between gas-phase and stellar metallicity in a large galaxy sample obtained from the MaNGA DR17 survey. We found that the gas metallicity is on average closely aligned with the stellar metallicity in the centers of intermediate-mass galaxies. Conversely, the difference is notably larger within the center of massive galaxies. It reaches about -0.18~dex on average for the most massive galaxies, while for low-mass galaxies, the gas metallicity exhibits a slightly lower value than the stellar metallicity. Moreover, the most prominent instances of a reduced gas-phase metallicity in relation to stellar metallicity were observed within the centers of massive red galaxies with low specific star formation rates. Because of the absence of a correlation between the integral mass fraction of neutral gas and the disparity between gas and stellar metallicity, we suggest that the diminished gas-phase metallicity in the centers of massive galaxies might be attributed to the replenishment of gas-depleted central regions through processes such as radial gas flows or accretion from the circumgalactic medium rather than gas infall from the intergalactic medium.