Spatially resolved mass–metallicity relation at z  ∼  0.26 from the MUSE-Wide Survey

¹ Department of Astronomy, University of Science and Technology of China, Hefei 230026, PR China
e-mail: yaoyao97@mail.ustc.edu.cn, xkong@ustc.edu.cn
² School of Astronomy and Space Sciences, University of Science and Technology of China, Hefei 230026, PR China
³ School of Astronomy and Space Science, Nanjing University, Nanjing 210093, PR China
⁴ Key Laboratory of Modern Astronomy and Astrophysics (Nanjing University), Ministry of Education, Nanjing 210093, PR China
⁵ Frontiers Science Center for Planetary Exploration and Emerging Technologies, University of Science and Technology of China, Hefei, Anhui 230026, PR China

Received: 13 January 2022
Accepted: 24 March 2022

Abstract

Aims. Galaxies in the local universe have a spatially resolved star-forming main sequence (rSFMS) and mass–metallicity relation (rMZR). We know that the global mass–metallicity relation (MZR) results from the integral of the rMZR, and it evolves with redshift. However, the evolution of the rMZR with redshift is still unclear because the spatial resolution and signal-to-noise ratio are low. Currently, too few observations beyond the local universe are available, and only simulations can reproduce the evolution of the rMZR with redshift.

Methods. We selected ten emission-line galaxies with an average redshift of z ∼ 0.26 from the MUSE-Wide DR1. We obtained the spatially resolved star formation rate (SFR) and metallicity from integral field spectroscopy (IFS), as well as the stellar mass surface density from 3D-HST photometry. We derived the rSFMS and rMZR at z ∼ 0.26 and compared them with those of local galaxies.

Results. We find that the rSFMS of galaxies at z ∼ 0.26 has a slope of ∼0.771. The rMZR exists at z ∼ 0.26, showing a similar shape to that of the local universe, but a lower average metallicity that is about ∼0.11 dex lower than the local metallicity. In addition, we also study the spatially resolved fundamental metallicity relation (rFMR) of these galaxies. However, there is no obvious evidence that an rFMR exists at z ∼ 0.26, and it is not an extension of rMZR at a high SFR.

Conclusions. Similar to their global versions, the rSFMS and rMZR of galaxies also evolve with redshift. At fixed stellar mass, galaxies at higher redshift show a higher SFR and lower metallicity. These suggest that the evolution of the global galaxy properties with redshift may result from integrating the evolution of the spatially resolved galaxy properties.