Institute for Advanced Study/Princeton University Joint Astrophysics Colloquium

The center of the Milky Way hosts the closest supermassive black hole and nuclear star cluster to the Earth, offering us the opportunity to study the physics of supermassive black holes and their environment at a level of detail not possible elsewhere. I will discuss three major questions that are at the forefront of Galactic center research: (1) Is General Relativity the correct description of supermassive black holes? (2) What is the nature of the near-infrared emission from Sgr A*? and (3) How do nuclear star clusters form and evolve in the vicinity of a supermassive black hole? I will show how the long time-baseline of Galactic center observations, improved instrumental capabilities, and use of statistical methods to combine many types of data have led us to new insights into these questions. I will discuss the measurement of the relativistic redshift from the star S0-2 as it went through its closest approach to the supermassive black hole in 2018, Sgr A*'s unusual activity in 2019, and the results from the first chemical-dynamical model of the Milky Way Nuclear Star Cluster.