Monica Valluri

Monica Valluri uses numerical calculations and simulations to probe observed galactic phenomena in order to understand the physical processes that produce them. Her current focus areas are supermassive black holes (see below) and the interactions between dark matter and luminous matter in galaxies. Her analysis of simulations of dark matter halos have shown, for example, why those with gas and stars tend to be rounder. It appears that the luminous matter serves to slightly deform dark matter particles’ box-shaped orbits, resulting in a halo that is rounder than if it were comprised solely of dark matter. The implication is that the orbits of the Milky Way’s stars might serve as a probe of its dark halo’s shape.

Notable Results

Valluri showed that tidal forces that affect the evolution of galaxies in clusters need not always rip them apart, but can produce “compressive shocking” when a galaxy passes through the dense dark matter cusp in a cluster’s center. Her “compressive shocking” analysis has subsequently been applied in a variety of other contexts, especially as a way to explain the intense bursts of star formation in the centers of galaxies. Valluri’s work on black holes has allowed her both to explain how they affect the shape of their host galaxies and to generate more accurate mass measurements for them. For the former, she showed (with David Merritt) that a central black hole (whose mass is about 1/1000th the mass of its host galaxy) can cause “chaotic scattering” of the orbits of a sufficient number of stars to transform the galaxy’s overall shape.

Background

BS/MS, Birla Institute of Technology and Science/India; PhD, Indian Institute of Science. Postdocs at Columbia University and Rutgers University; Research Scientist and Assistant Director of the Kavli Institute for Cosmological Physics, University of Chicago

Publications

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