I am an astrophysicist, which is a wonderful job: I get to look at the stars and figure out how the Universe works! My research focuses on many aspects of galaxy clusters. In particular, I use weak gravitational lensing to calibrate mass estimates of clusters, a central ingredient for cluster cosmology. I am also interested in the properties of cluster galaxies, in particular Brightest Cluster Galaxies, and their evolution.

We have recently completed the Weighing the Giants project, showing that weak-lensing cluster mass estimates can enable some of the tightest constraints on dark energy from a single probe.  I continue this work within the LSST Dark Energy Science Collaboration, the South Pole Telescope survey, the Euclid space mission, and the WFIRST project.