Gas metallicity distributions in SDSS-IV MaNGA galaxies: what drives gradients and local trends?

Nicholas Fraser Boardman*, Vivienne Wild, Tim Heckman, Sebastián F. Sánchez, Rogério Riffel, Rogemar A. Riffel, Gail Zasowski

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


The gas metallicity distributions across individual galaxies and across galaxy samples can teach us much about how galaxies evolve. Massive galaxies typically possess negative metallicity gradients, and mass and metallicity are tightly correlated on local scales over wide range of galaxy masses; however, the precise origins of such trends remain elusive. Here, we employ data from SDSS-IV MaNGA to explore how gas metallicity depends on local stellar mass density and on galactocentric radius within individual galaxies. We also consider how the strengths of these dependencies vary across the galaxy mass-size plane. We find that radius is more predictive of local metallicity than stellar mass density in extended lower mass galaxies, while we find density and radius to be almost equally predictive in higher-mass and more compact galaxies. Consistent with previous work, we find a mild connection between metallicity gradients and large-scale environment; however, this is insufficient to explain variations in gas metallicity behaviour across the mass-size plane. We argue our results to be consistent with a scenario in which extended galaxies have experienced smooth gas accretion histories, producing negative metallicity gradients over time. We further argue that more compact and more massive systems have experienced increased merging activity that disrupts this process, leading to flatter metallicity gradients and more dominant density-metallicity correlations within individual galaxies.
Original languageEnglish
Article numberstad277
Pages (from-to)4301–4314
Number of pages14
JournalMonthly Notices of the Royal Astronomical Society
Issue number3
Early online date21 Feb 2023
Publication statusPublished - 1 Apr 2023


  • Galaxies: ISM
  • Galaxies: structure
  • Galaxies: general
  • ISM: general
  • Galaxies: statistics
  • ISM: abundances


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