Princeton University Thunch Talk

Abstract: On April 10, 2019, the Event Horizon Telescope captured the world’s imagination with the first direct image of a black hole. LEO VLBI Pathfinder is a SmallSat mission led by Brown University which seeks to take the next leap: Capturing the first video of a black hole. How? A video is worth a thousand pictures, and a picture, in turn, is worth a thousand words. Thus, to capture a video of a black hole, one must sample > 50% of the target in the fourier (u, v) domain on sub-ISCO timescales (t < 30 min). This is difficult from ground stations, where Earth-Rotation Aperture Synthesis is restricted by the Earth’s rotational period. Thus, LEO VLBI Pathfinder will launch into low-earth orbit, where it will orbit the earth at 7.2 km/s, directly imaging Sgr A* every 22 minutes, enabling rapid and dense radio coverage of black hole targets. These images will be stacked atop each other to create a video, enabling tracking of hotspots in the accretion disk, constraints on the spin of Sgr A*, and testing of the Blandford-Znajek mechanism.