Colloquium

The Precision Frontier of Dark Matter Constraints from Direct Acceleration Measurements

Speaker: Sukanya Chakrabarti (University of Alabama, Huntsville)

Date and time

Abstract

For over a century, our understanding of dark matter has hinged on kinematic estimates derived from a snapshot of the positions and speeds of stars. However, this analysis is inaccurate for a time-dependent potential, and there are now many lines of evidence that show that our Galaxy has had a highly dynamic history.  Recent technological advances now enable us to carry out extremely precise time-series measurements of the acceleration of stars that live within the gravitational potential of our Galaxy.  I will discuss our comprehensive observational strategy to directly measure Galactic accelerations. Central to this discussion is our recent analysis of compiled pulsar timing data from which we were able to measure the Galactic acceleration for the first time, and derive fundamental Galactic parameters. Discernible differences in sub-structure exist among popular dark matter models on small scales, presenting testable nuances. I will discuss the potential for measuring dark matter sub-structure in the Milky Way by leveraging the set of techniques we have developed, including pulsar timing, eclipse timing, and extreme-precision radial velocity observations. I will review initial results from our multi-pronged observing campaign, and end by discussing synergies between Galactic dark matter constraints and constraints on theories of gravity.

Sukanya Chakrabarti

Short Biography
Professor Sukanya Chakrabarti is the Pei-Ling Chan Endowed Chair in the department of physics and astronomy at the University of Alabama Huntsville. She has worked broadly across many areas of astronomy, and recently has led the development of techniques and observing campaigns to directly measure the small accelerations of stars that live within the gravitational potential of the Milky Way, which provide the most direct probe of the mass distribution in the Galaxy. These recent measurements now enable the new, highly interdisciplinary field of “real-time” Galactic dynamics that brings together the exoplanet community, researchers in compact objects and eclipsing binaries, and in traditional Galactic dynamics. She received her Ph.d. in physics from UC Berkeley and held postdoctoral fellowships at Harvard and Berkeley. She was earlier a Scialog Fellow and IBM-Einstein Fellow, as well as the Vera Rubin Distinguished Visiting Professor at UCSC, and will be the upcoming Margaret Burbidge visiting Professor at UCSD.