Does the accelerating expansion of the universe require a modification to our theories of gravity or does there exist some new form of energy, so-called ​‘Dark Energy?’ Dr. Bleem seeks to answer such questions by studying of clusters of galaxies---the largest gravitationally-bound systems in the universe. Their abundance is a powerful cosmological probe as it depends upon both the expansion history of the universe and the growth of density fluctuations. A member of the South Pole Telescope collaboration, her research interests also include large-scale structure, the cosmic microwave background, and the development of bolometric detectors for measurements of the millimeter-wave sky.