The MAGPI Survey: forward modelled gas-phase metallicity gradients in galaxies at z ∼ 0.3

Journal article

We measure the seeing-deconvolved gas-phase metallicity gradients of 70 star-forming galaxies at from the MAGPI survey and investigate their relationship with galaxy properties to understand the mechanisms that influence the distribution of metals and shape the evolution of the galaxies. We use a Bayesian modelling technique, blobby3d, which accounts for seeing effects (beam smearing) and can model the substructures of the flux distribution. The median metallicity gradient of our sample is dex kpc−1. Among the galaxies in our sample, 32.9 per cent have negative metallicity gradients (2 significance), 10.0 per cent have positive gradients and 57.1 per cent have flat gradients. The – relation of the MAGPI galaxies generally agrees with theoretical predictions, where a combination of stellar feedback, gas transport, and accretion shapes the metallicity profile, with the dominant processes varying with galaxy mass. We find a positive correlation between and gas velocity dispersion (), indicating that stronger gas turbulence is associated with flatter or inverted metallicity gradients, likely due to enhanced gas mixing. Additionally, smaller galaxies tend to have flatter or positive gradients, suggesting that metal dilution by gas accretion or removal via feedback-driven winds may outweigh metal enrichment in small galaxies.

Authors: Mai, Y; Croom, SM; Wisnioski, E; Battisti, AJ; Mendel, JT

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Oxford University Press
• Journal: Monthly Notices of the Royal Astronomical Society
• Volume: 545
• Issue: 3
• Pages: staf2182
• Article number: staf2182
• Publication date: 2025-12-10
• Acceptance date: 2025-12-04
• DOI: 10.1093/mnras/staf2182
• EISSN: 1365-2966
• ISSN: 0035-8711
• Language: English
• Keywords: galaxies: abundances; galaxies: ISM; galaxies: formation; galaxies: evolution