Friday

The levels of heavy elements in stars are the product of enhancement by previous stellar generations, and the distribution of this metallicity among the population contains clues to the process by which a galaxy formed. We present analysis from our most recent paper, in which we measure metallicity distributions for a large sample of spiral galaxies, using high quality spectral data obtained by the SDSS-IV MaNGA survey. We find that high-mass spirals generically show a deficit of low-metallicity stars, implying that gas accretion is common in such galaxies. This is behaviour similar to what has classically been observed in the Milky Way. By contrast, low-mass spirals exhibit metallicity distributions that would be expected if such systems evolved as closed boxes. This distinction can be understood from the differing timescales for star formation in galaxies of differing masses. Furthermore, we also discuss our ongoing project, in which we endeavour to investigate the interplay between stellar and gas-phase metallicity in the same sample of spiral galaxies. More specifically, we determine both the stellar and gas-phase metallicity histories of these galaxies, in addition to their star formation histories. It is our hope that measuring the progression of these properties over cosmic time will allow us to unravel the cosmic evolution histories of spiral galaxies, as well as furthering our understanding of how the timescale of star formation varies according to stellar masses of such galaxies.