Jiayi Sun

Team Member Profile: Jiayi Sun

Position: Postdoctoral Fellow at McMaster University

Professional webpage: https://astrojysun.github.io

General science interest: I would like to understand the physical processes shaping the cold interstellar medium in galaxies. I specialize in the study of molecular gas through millimeter-wave observations. My current main focus is on characterizing the demographics of molecular clouds and their links to star formation, stellar feedback, and galaxy dynamics.


My role in PHANGS: With the PHANGS-ALMA CO(2-1) data, I extract more than 100,000 indepedent measurements of molecular gas properties on 50-150 parsec scales across the local star-forming galaxy population (Sun et PHANGS 2018; Sun et PHANGS 2020b). I use this unprecedented sample of measurements to demonstrate how molecular clouds characteristics vary within a galaxy and among galaxies. I further assemble a rich value-added dataset that combines these molecular cloud measurements with a full inventory of gas and stellar mass distribution, kinematic information, morphological structures, and star formation activities in the host galaxy (Sun et PHANGS 2022 in prep.). This value-added dataset has supported (and will continue to support) a wide range of PHANGS projects on the multi-phase ISM, stellar disk structures, star clusters, gas outflows, star formation efficiencies, and galaxy disk instabilities (Herrera et PHANGS 2020; Sun et PHANGS 2020a; Barnes et PHANGS 2021;Querejeta et PHANGS 2021; Stuber et PHANGS 2021; Deger et PHANGS 2022 in prep.; Utomo et PHANGS 2022 in prep.; Williams et PHANGS 2022 in prep).


This figure demonstrates how molecular gas properties on 120 parsec scales vary within and across galaxies (see Sun, J. and the PHANGS Collaboration, 2018). The spread in molecular gas surface density and velocity dispersion (top), dynamical state (bottom left), and turbulent pressure (bottom right) is evident across the 15 nearby galaxies examined. There is also a clear contrast between normal star-forming galaxies (blue, including 11 PHANGS-ALMA targets), a merger system (orange), and two more quiescent galaxies (green).