What drives stellar population evolution?

The stellar population of a galaxy contains a record of its star formation and assembly history, making it an important area of research to develop our understanding of galaxy formation and evolution. We present two works, the first focussing on early-type galaxies (ETGs), the second on late-types (LTGs). These works aim to understand the link between the overall structure and dynamics of a galaxy, and the evolution of the stars within it. Currently, the well-established correlations between the mass of a galaxy and the properties of its stars are considered evidence for mass driving the evolution of the stellar population. However, for our sample of 625 early-type galaxies (ETGs) with integral-field spectroscopy from the SAMI Galaxy Survey, compared to correlations with mass, the color—gravitational potential ($\Phi$), [Z/H]--$\Phi$, and age—surface density ($\Sigma$) relations show both smaller scatter and less residual trend with galaxy size. These results lead us to the following inferences: (1) the color--$\Phi$ diagram is a more precise tool for determining the developmental stage of the stellar population than the conventional color--$M$ diagram; and (2) gravitational potential is the primary regulator of global stellar metallicity, via its relation to the gas escape velocity. More recently, we've extended this research to investigate the stellar populations of late-type galaxies (LTGs) using single-fibre spectra from the Sloan Digital Sky Survey.