Imaging the Unseen: Taking the First Picture of a Black Hole
TimeTuesday, 19 November 201910:30am - 11:15am
DescriptionThis talk presents the methods and procedures used to produce the first image of a black hole from the Event Horizon Telescope. It has been theorized for decades that a black hole will leave a "shadow" on a background of hot gas. Taking a picture of this black hole shadow could help to address a number of important scientific questions, both on the nature of black holes and the validity of general relativity. Unfortunately, due to its small size, traditional imaging approaches require an Earth-sized radio telescope. In this talk, I discuss techniques we have developed to photograph a black hole using the Event Horizon Telescope (EHT), a network of telescopes scattered across the globe. Imaging a black hole’s structure with this computational telescope requires us to reconstruct images from sparse measurements, heavily corrupted by atmospheric error. The resulting image is the distilled product of an observation campaign that collected approximately five petabytes of data over four evenings in 2017. The process for recording, correlating, calibrating, and imaging the data has been built-out by the EHT over the last decade. We will summarize how the data from the 2017 observations were calibrated and imaged, and we will explain some of the challenges that arise with a heterogeneous telescope array like the EHT.