Abstract：In this talk, I will discuss several observational anomalies uncovered by recent JWST observations and explore their implications for our understanding of early galaxy formation. I will first review the evolution of modern cosmological hydrodynamical simulations that resolve the multiphase interstellar medium, highlighting two key outcomes that may explain many of the JWST puzzles: bursty star formation and enhanced star-formation efficiency. Specifically, I will present insights into these two phenomena from our recent THESAN-ZOOM simulation campaign. Finally, I will broaden the discussion to consider how modifications to the underlying cosmological model (without altering canonical galaxy formation physics) might also account for these anomalies. JWST has brought us to a pivotal moment, offering an unprecedented opportunity to refine both our galaxy formation models and cosmological framework.
Bio: Xuejian (Jacob) is a postdoctoral researcher at the Kavli Institute for Astrophysics and Space Research at Massachusetts Institute of Technology. Xuejian received the Bachelor’s degree from Peking University and the Ph.D. degree in Physics at the California Institute of Technology supervised by Prof. Philip Hopkins. His research interests are the formation and evolution of high-redshift galaxies and supermassive black holes in light of JWST observations, and the potential of using high-redshift observables constraining fundamental physics. He is also part of the FIRE and THESAN collaboration in developing novel cosmological radiation-hydrodynamic simulations of high-redshift galaxies.