[Colloquium] Cosmological Puzzles From JWST

Julian B. Muñoz, UT Austin

Title: Cosmological Puzzles From JWST

Abstract: The James Webb Space Telescope (JWST) has revolutionized our understanding of the early universe through its unprecedented infrared capabilities. This talk will explore several tensions that are emerging between early JWST observations and our standard cosmological models. I will discuss the discovery of surprisingly abundant and luminous high-redshift galaxies, and how Hubble data constrain these "universe breakers" to have astrophysical rather than cosmological explanations. Next, I'll demonstrate how to use early-galaxy data to test the nature of dark matter at small scales. Finally, I will examine how recent JWST determinations of cosmic reionization are at odds with complementary cosmological probes, including the CMB and the Lyman-alpha forest, and discuss the implications for both cosmology and astrophysics.