NASA’s James Webb Space Telescope is offering the most detailed view yet of the turbulent activity surrounding the supermassive black hole at the heart of the Milky Way. The telescope has captured a steady flickering of light, occasionally interrupted by bright flares, as matter is pulled inward by the black hole’s immense gravity. Launched in 2021 and operational since 2022, Webb allows astronomers to observe Sagittarius A* (Sgr A*) for extended periods, revealing patterns of activity that were previously hidden by background noise.
This new study is the first to use Webb’s ability to detect a spectrum of light that spans a broad range of wavelengths, revealing how the violent events in and around Sgr A* can change over time. The researchers analyzed a sample of the bright flares in the accretion disk, a swirling disk of gas and dust surrounding the black hole. They discovered that over a short period, the brightness of the flares dimmed faster at shorter wavelengths than at longer wavelengths. This is typical behavior for particles that are losing energy as they spiral around magnetic field lines near the black hole, according to the research team led by Northwestern University Professor of Physics and Astronomy Amir Yusef-Zadeh.
The scientists also observed the flares in different colors based on their intensity and rotation speed. They found that the brightest flares had the fastest spin. The team said these fast-spinning particles appear to be a significant source of energetic activity around the black hole. The findings were published in Friday’s Science Advances.
Yusef-Zadeh and his colleagues want to use JWST to observe Sgr A* for a longer, uninterrupted 24 hours to reduce the overall noise level and see finer details. The goal is to see if we can witness more of this activity and build a knowledge base, determining what patterns might exist. The researchers also plan to apply their new understanding of Sgr A* to other black holes to learn what is universal about them and what makes each unique.
The next significant milestone for Webb is expected to occur this week, when it will begin camping out in orbit around a point in space called the Earth-sun Lagrange point 2, or L2. It took the observatory more than 740,000 miles to reach that destination, and it has 160,000 miles left before it is fully deployed. Astronomers will start adjusting to the 18 mirror segments comprising Webb’s primary mirror starting on Jan. 11. Follow along as it campouts in the shadow of the Sun and the giant black hole at the center of our galaxy.
