Scientists believe that the environment surrounding a black hole is filled with hot magnetized gas that spirals in a disk at high speeds and temperatures. Flares are observed in this disk, brightening and fading multiple times a day. A team led by Caltech scientists has used telescope data and an artificial intelligence technique to create the first 3D video showing what these flares could look like around Sagittarius A*, the supermassive black hole at the center of the Milky Way galaxy. The structure features two bright, compact features located about 75 million kilometers from the black hole and was based on data collected by ALMA in Chile after an eruption on April 11, 2017.
The 3D reconstruction is not a direct recording of events as they occurred, but rather a representation based on black hole physics models. The team had to develop computational imaging tools to account for the bending of light due to the curvature of space-time around the black hole. By integrating physics into artificial intelligence, they were able to create a 3D structure of the gas rotating close to the black hole. Leveraging recent developments in neural network representations, they were able to reconstruct the 3D environment around the black hole, despite the challenge of only having a single viewpoint from Earth.
ALMA data from April 11, 2017, captured a sudden brightening in the surroundings of Sgr A*, the supermassive black hole at the galactic center. ALMA provides light curves, essentially videos of single flickering pixels, which the team used to recover a 3D volume around the black hole. The strongly polarized light coming from the flares helped the scientists pinpoint where the emissions were coming from in 3D space. The team developed a technique called Orbital Polarimetric Tomography, which incorporated the polarized emission expected in hot spots orbiting a black hole to create a likely 3D structure that matched the observations.
The team’s interdisciplinary collaboration between computer scientists and astrophysicists allowed them to develop cutting-edge methods that model how light propagates around black holes and create accurate computational imaging of black hole events. The resulting video shows two bright regions moving in a clockwise direction around the black hole, aligning with predictions from computer simulations of black holes. The scientists note that this technology has vast potential for studying other complex events in space and hope that astronomers will use it to shed more light on the dynamics of such phenomena.
Overall, this study showcases the fusion of artificial intelligence and physics to reveal unseen events around black holes. This innovative approach has provided a unique perspective on the dynamics of gas flares around Sagittarius A*, offering exciting possibilities for future research in understanding the behavior of black holes and other astronomical phenomena. The team’s groundbreaking work opens up new avenues for astronomers to explore complex physical processes and draw significant conclusions from rich time-series data.
