Beasts in the Bubbles: Discovering the origins of the first massive galaxies with JWST

Recent observations of the early universe have suggested the impossible: an abundance of ultra-massive, dead galaxies already within 1.5 billion years after the big bang. These ‘cosmic beasts’ must have been among the first galaxies to form, assembling their mass in a luminous burst of star-formation – releasing enough energy to reionize ‘bubbles’ of intergalactic hydrogen < 500 Myr after the Big Bang. Yet, their existence challenges contemporary models of galaxy formation. I will utilize the first observations with JWST to identify their star-forming progenitors, characterize their properties, assess their contribution to reionization, and critically test models of galaxy formation. My Cycle 1 program to observe five massive z ∼ 9 beasts is uniquely suited to the task, and will provide insight into the formation of the first massive galaxies to light up the cosmos.

John R. Weaver
John R. Weaver
PhD Fellow in Astrophysics

My research interests lie almost exclusively within the realm of extragalactic astrophysics and cosmology. I use state-of-the-art optical and infrared observatories and surveys to study the lives of galaxies, and how their properties change over cosmic time. This includes detailed case studies of individual galaxies, as well as statistical analyses of large survey catalogs.