Dr. Paul Torrey, University of Virginia

Title: Simulating the Universe: From Illustris to DREAMS

Abstract: Over the past few decades, cosmological simulations have revolutionized how we study galaxy formation and the large-scale structure of the universe. By combining advances in computational methods, physical modeling and high-performance computing, these simulations now allow us to trace the evolution of cosmic structure from the earliest moments after the Big Bang to the richly structured galaxies we observe today. 

Projects such as Illustris and IllustrisTNG have provided detailed, physically grounded predictions for how galaxies form and evolve, capturing the interplay among dark matter, gas dynamics, star formation and feedback from supermassive black holes. The publicly released data from these simulations have become a cornerstone of modern extragalactic astrophysics, powering thousands of scientific studies worldwide and shaping how we interpret observations across wavelengths and cosmic time. 

In this talk, I will highlight some of the key insights these simulations have revealed, emphasizing both their predictive successes and the limits of our current physical understanding. I will also discuss how new approaches, specifically the DREAMS simulation framework, are enabling us to quantify uncertainty across large, high-resolved cosmological ensembles, transforming simulations from single “best guess” models into powerful statistical laboratories for testing theories of galaxy formation.