Astrophysicists have utilized NASA's James Webb Space Telescope (JWST) to conduct an extensive observation of the supermassive black hole at the center of the Milky Way, known as Sagittarius A*. The study, led by Northwestern University's Farhad Yusef-Zadeh, revealed that the accretion disk surrounding this black hole is continuously emitting flares without any periods of inactivity. These findings were published in The Astrophysical Journal Letters.
The research team observed Sagittarius A* for a total of 48 hours over a year using JWST's near-infrared camera (NIRCam). This enabled them to track changes in the black hole's activity over time. "Flares are expected to happen in essentially all supermassive black holes, but our black hole is unique," said Yusef-Zadeh. "It is always bubbling with activity and never seems to reach a steady state."
Yusef-Zadeh explained that while some flares are short and faint, others are bright and last longer. He suspects two separate processes may be responsible for these different types of flares. Minor disturbances within the accretion disk likely generate faint flickers, similar to solar flares on the sun. In contrast, magnetic reconnection events could cause larger, brighter flares.
The study also found a time delay between events observed at different wavelengths. "This is the first time we have seen a time delay in measurements at these wavelengths," noted Yusef-Zadeh.
Yusef-Zadeh plans to continue observing Sagittarius A* for an uninterrupted 24-hour period to gain further insights into its behavior. "If we can observe for 24 hours, then we can reduce the noise to see features that we were unable to see before," he said.
The research was supported by NASA and the National Science Foundation.