We've been awarded JWST Cycle 1 time!

PI Weaver | ‘Beasts in the Bubbles’ will explore five galaxies seen at the dawn of the cosmos (z~9)

See the Program Information on the Space Telescope Science Institute’s Website


We propose restframe UV and optical spectroscopy to confirm redshifts and measure star-formation rates, stellar masses, and dust extinction for the five most luminous galaxies at 9<z<10 over two square degrees of the COSMOS survey. The unique combination of a wide-field near-infrared imaging coupled with new ultra-deep optical and infrared data makes this the most secure sample of 9<z<10 galaxy candidates currently available. However, these objects are too rare to be found by very deep, but smaller surveys with JWST, and the serendipitous discovery of even one such galaxy outside of COSMOS is unlikely from the entirety of planned GTO and ERS programs. These massive, luminous galaxies, seen only 500 million years after the Big Bang, are ideal tracers of the primordial dark matter structures from which they formed and grew. However, their mere existence at these early times challenges the current paradigm of early galaxy formation and evolution. Thus, it is essential to confirm their high redshift nature and reveal the means by which these remarkable cosmic beasts so rapidly built up their stellar mass.

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.