H.B. Keller Colloquium

The Event Horizon Telescope (EHT) is a unique computational camera with a goal of imaging the imprint of a black hole on a backdrop of glowing gas. In May of 2022 the EHT collaboration revealed the first images of the black hole at the center of our Milky Way galaxy: Sagittarius A* (Sgr A*). This image was computationally reconstructed from sparse and noisy measurements collected from synchronized telescopes around the globe. Imaging Sgr A* proved especially challenging due to its evolution, which is dynamic on the timescale of acquisition. In this talk I will summarize how the first black hole images were recovered from the EHT data and highlight the challenges that had to be addressed in order to capture an image of Sgr A*, including newly developed methods we used to characterize the uncertainty. Although we have learned a lot from these images already, remaining scientific questions motivate us to improve this computational telescope to see black hole phenomena still invisible to us. This talk will also highlight future directions and how we are developing physics-informed machine learning methods that will allow us to extract the evolving structure of Sgr A* over the course of a night in the future, perhaps even in three dimensions.