SDSS-IV MaNGA: drivers of stellar metallicity in nearby galaxies
Abstract
The distribution of stellar metallicities within and across galaxies is an excellent relic of the chemical evolution across cosmic time. We present a detailed analysis of spatially resolved stellar populations based on >2.6 million spatial bins from 7439 nearby galaxies in the Sloan Digital Sky Survey-IV (SDSS-IV) Mapping Nearby Galaxies at APO (MaNGA) survey. To account for accurate inclination corrections, we derive an equation for morphology-dependent determination of galaxy inclinations. Our study goes beyond the well-known global mass-metallicity relation and radial metallicity gradients by providing a statistically sound exploration of local relations between stellar metallicity [Z/H], stellar surface mass density Σ⋆, and galactocentric distance in the global mass-morphology plane. We find a significant resolved mass density-metallicity relation $r\Sigma _\star ZR$ for galaxies of all types and masses above $10^{9.8}\, \mathrm{M_\odot }$. Different radial distances make an important contribution to the spread of the relation. Particularly, in low- and intermediate-mass galaxies, we find that at fixed Σ⋆ metallicity increases with radius independently of morphology. For high masses, this radial dependence is only observed in high Σ⋆ regions of spiral galaxies. This result calls for a driver of metallicity, in addition to Σ⋆ that promotes chemical enrichment in the outer parts of galaxies more strongly than in the inner parts. We discuss gas accretion, outflows, recycling, and radial migration as possible scenarios.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- December 2021
- DOI:
- 10.1093/mnras/stab2868
- arXiv:
- arXiv:2109.11564
- Bibcode:
- 2021MNRAS.508.4844N
- Keywords:
-
- techniques: spectroscopic;
- galaxies: abundances;
- galaxies: evolution;
- galaxies: statistics;
- galaxies: stellar content;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 16 pages, 11 figures. MNRAS accepted, pending a few minor revisions