Sukanya Chakrabarti (RIT) --- Fundamental Galactic Parameters from Direct Acceleration Measurements


For more than a century now, astronomers have modeled the positions and velocities of stars to estimate accelerations (i.e., using kinematic analysis). Recent observations have revealed that our Galaxy has had a highly dynamic history. For time-dependent potentials (like that of our Galaxy), there are discrepancies between the true acceleration and that derived from kinematics. I will review two independent methods to directly measure the accelerations of stars in the Milky Way to enable what I call "real-time Galactic dynamics". I will first review our work on measuring accelerations from high precision RV observations conducted over about decade-long baselines. In particular, I will discuss theoretical expectations of the vertical acceleration profile that are motivated by Gaia observations. I will then talk about our analysis of pulsar timing observations, from which we were able to measure Galactic accelerations for the first time, and from these measurements, derive fundamental Galactic parameters, including the Oort limit, the local dark matter density, and the oblateness of the Galactic potential. I will end by talking about prospects for measuring Galactic accelerations in the Gaia-Roman era, and the possibility for developing an “acceleration ladder”.