Jason Tumlinson

Associate Astronomer w/ Tenure

Jason Tumlinson has worked as an observational and theoretical astronomer spanning multiple areas of astrophysics since beginning his PhD studies in 1998. As an observer he has been the PI of the “COS-Halos” project, a 277-orbit program with Hubble’s Cosmic Origins Spectrograph that has made several significant discoveries about the nature of the gaseous Circumgalactic Medium (CGM) that helps to form and feed galaxies. This program has generated a number of high-impact publications, including the most cited paper based on COS data (Tumlinson et al., Science, 334, 938). As a theorist, he was among the first to publish realistic stellar evolution models and ionizing photon outputs for primordial stars (Tumlinson & Shull 2000; Tumlinson, Venkatesan, & Shull 2003). He was an early proponent of using the fossil record of chemical abundances to constrain the first stars IMF (Tumlinson et al. 2004, 2010). This work ultimately led to a state-of-the-art Hubble imaging program to obtain the star- formation histories and IMFs of the Ultra-faint Dwarf galaxies with HST/ACS (Brown et al. 2012; Geha et al. 2013). This work has made key predictions about the first stars that will soon be tested by JWST.

At STScI, Tumlinson has held instrument scientist positions with JWST, led the definition of JWST parallel observing, and co-created the Hubble Spectroscopic Legacy Archive. He is now the Deputy Head of the Community Missions Office, where he leads the Institute's role in the TESS mission and its involvement with the planning and development of future space astronomy missions.


PhD in Astrophysics, University of Colorado, Boulder 2002
MS in Astrophysics, University of Colorado, Boulder 1999
BA in Physics, Rice University 1997


Research Topics: Local Group Galaxies; Galaxy Formation and Evolution; Stellar Populations; Circumgalactic Medium


Professional Websites:

Professional Website


ORCID ID: 0000-0002-7982-412X

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