The chemical evolution carousel of spiral galaxies: a 3D view of ISM metallicity with PHANGS-MUSE and TYPHOON

The spatial distribution of the interstellar medium oxygen abundance is the key to understanding how efficiently metals synthesized in massive stars can be redistributed across a galaxy. One way to understand how efficient ISM mixing occurs on orbital timescale is to probe chemical inhomogeneity in the azimuthal direction. Despite decades of studies, evidence of the presence of azimuthal variations of chemical abundances remains circumstantial. In this talk, I will present some of the highest spatial resolution 3D spectroscopic data collected by the PHANGS collaboration with MUSE and the TYPHOON Program with the du Pont telescope. These high quality data begin to approach a critical spatial scale of typical giant molecular cloud and HII region (50 to100 pc), allowing us to study the ISM chemistry and star formation in unprecedented details. I will show compelling evidence that the ISM oxygen abundance changes systematically in the azimuthal direction. The abundance variations spatially correlate with the spiral structures and are imprinted on negative radial gradients. I will place the observations in the framework of a simple chemical evolution model and demonstrate that the variations could be driven by a combination of environmentally dependent mixing time and star formation density. I will end the talk by discussing future prospects of using the ongoing MUSE and ALMA large programs by the PHANGS collaboration to advance our understanding of chemical abundances and mixing on sub-kiloparsec scale