At The Break of Cosmic Dawn - Understanding the First Galaxies with JWST

The first few hundred million years after the Big Bang mark a fundamental transition in cosmic history, when the earliest galaxies assembled and began to fundamentally change the Universe. Yet until recently, this era was accessible only in theory, leaving a central question unresolved: how quickly, and by what physical processes, did the first galaxies form and evolve? With the James Webb Space Telescope (JWST), we now have direct access to this epoch. As a member of the JWST Advanced Deep Extragalactic Survey (JADES), I have focused on identifying and physically characterizing galaxies seen from the first few hundred million years after the Big Bang. In this talk, I will present new results from ultra-deep JWST observations in GOODS-S and GOODS-N, and I will discuss what the galaxies seen in these field reveal about early formation of stars and heavy elements. These galaxies appear to be brighter, and in some cases more chemically evolved than many pre-JWST expectations, challenging simple models of galaxy evolution, and raising new questions about how galaxies assembled at early times. Together, these results define a forward research program focused on rigorous sample construction, improved distance validation, and physically grounded modeling of galaxies in the first 300 million years, laying the groundwork for precision studies of cosmic reionization with JWST and beyond.

Apr 22, 2026 12:00 AM