Woorak Choi is a postdoctoral fellow at McMaster University. He completed his PhD in 2024 at Yonsei University, South Korea. Woorak's research focuses on understanding the evolution of the ISM and star formation in extreme environments, ranging from galactic centers to galaxy clusters. As a radio astronomer, he primarily uses radio telescopes such as ALMA and VLA, but has recently begun working with JWST data. Woorak is also interested in incorporating numerical simulations to complement observational studies.
Title: Understanding Ram Pressure Stripping Through High-Resolution MHD Simulations and VLA Continuum Observations
Abstract: In this seminar, I will present an integrated study of ram pressure stripping (RPS), combining results from high-resolution MHD simulations and VLA continuum observations of the stripped galaxy NGC 4522, to explore its role in galaxy evolution. The simulations incorporate a more realistic multiphase ISM to reveal that RPS is driven by mixing-driven momentum transfer, where the hot intracluster medium (ICM) shreds the porous interstellar medium and forms cooling, mixed layers, predicting an anticorrelation between stripped gas velocity and metallicity. Observationally, the radio continuum data shows a strong asymmetry and an unexpectedly flat spectral index in extraplanar clouds, suggesting that ICM-ISM mixing is significantly likely to enhance thermal emission independently of star formation, a mechanism directly supported by the simulations. Together, these studies demonstrate that RPS is a complex, multiphase process involving substantial energy transfer and mixing, providing crucial insights into how the ICM shapes galactic gas dynamics/properties and ultimately quenches star formation.