The MAGPI survey: evolution of radial trends in star formation activity across cosmic time
Ellison, Sara L.; Gupta, Anshu; Mendel, J. Trevor; Lagos, Claudia D. P.; Grasha, Kathryn; Foster, Caroline; Battisti, Andrew J.; Bellstedt, Sabine; Sweet, Sarah M.; Wisnioski, Emily; Taylor, Edward N.; Croom, Scott M.; Zafar, Tayyaba; Remus, Rhea-Silvia; Sharda, Piyush; Valenzuela, Lucas M.; Park, Hye-Jin; Chen, Qian-Hui; Mun, Marcie; Barsanti, Stefania; Harborne, Katherine E.; Mukherjee, Tamal
Australia, Canada, Germany, Netherlands
Abstract
Using adaptive optics with the Multi-Unit Spectroscopic Explorer on the Very Large Telescope, the Middle Ages Galaxy Properties with Integral Field Spectroscopy survey allows us to study the spatially resolved Universe at a crucial time of ~4 Gyr ago (z ~ 0.3) when simulations predict the greatest diversity in evolutionary pathways for galaxies. We investigate the radial trends in the star formation (SF) activity and luminosity-weighted stellar ages as a function of offset from the star-forming main sequence (SFMS) for a total of 294 galaxies. Using both Hα emission and the 4000 Å break (i.e. D4000) as star formation rate (SFR) tracers, we find overall flat radial profiles for galaxies lying on and above the SFMS, suggestive of physical processes that enhance/regulate SF throughout the entire galaxy disc. However, for galaxies lying below the SFMS, we find positive gradients in SF suggestive of inside-out quenching. Placing our results in context with results from other redshift regimes suggests an evolution in radial trends at z ~ 0.3 for SF galaxies above the SFMS, from uniformly enhanced SF at z ~ 1 and ~ 0.3 to centrally enhanced SF at z ~ 0 (when averaged over a wide range of mass). We also capture higher local SFRs for galaxies below the SFMS compared to that of z ~ 0, which can be explained by a larger population of quenched satellites in the local Universe and/or different treatments of limitations set by the D4000-sSFR relation.