I am a Professor in the Department of Astronomy at the University of California, Berkeley. My research group works on observations of the first generations of galaxies, low metallicity stellar populations, and the reionization of intergalactic hydrogen. 

Prior to moving to Berkeley, I was a Professor (2013-2024) and Hubble Fellow (2011-2013) at the University of Arizona. Before moving to Tucson, I spent three years as an STFC Postdoctoral Fellow at the University of Cambridge (2008-2011).  

I completed my PhD at the California Institute of Technology in 2008, working with Richard Ellis on high redshift galaxies and reionization, and I did my undergraduate studies at the University of Wisconsin. 

More information on the topics my research group is investigating can be found here. In the next year, our efforts will be focused on a series of JWST Cycle 4 programs, GO 9214 (co PIs Mason and Stark), GO 9016 (PI Stark), GO 9165 (co PIs Endsley and Stark), each of which targets the most distant galaxies known with ultra-deep spectroscopy. 

I recently wrote a review article with members of my research group describing progress in our understanding of the first galaxies and reionization following two years of JWST observations, providing an update to an earlier ARAA article I wrote in 2016.