What determines the local metallicity of galaxies: global stellar mass, local stellar mass surface density or star formation rate?

Understand

The metallicity and its relationship with other galactic properties is a fundamental probe of the evolution of galaxies.

• In this work, we select about 750,000 star-forming spatial pixels from 1122 blue galaxies in the MaNGA survey to investigate the global stellar mass - local stellar mass surface density - gas-phase metallicity ($M_*$ - $\Sigma_*$ - $Z$ ) relation.
• At a fixed $M_*$, the metallicity increases steeply with increasing $\Sigma_*$.
• Similarly, at a fixed $\Sigma_*$, the metallicity increases strongly with increasing $M_*$ at low mass end, while this trend becomes less obvious at high mass end.