Black Hole at the Heart of Our Galaxy Observed in Dynamic ‘Bubbling’ Activity

NASA’s James Webb Space Telescope (JWST) has revealed an unexpected cosmic light show around Sagittarius A*, the supermassive black hole at the center of the Milky Way. Although not as ravenous as other black holes in the universe, its surroundings flare with bursts of activity, creating what researchers describe as “fireworks.”

Using JWST’s Near-Infrared Camera (NIRCam), astronomers observed Sagittarius A* for 48 hours, spread across multiple sessions over a year. They detected frequent cosmic flares—five to six major bursts daily, along with several smaller ones. The findings, published in The Astrophysical Journal Letters, indicate that the black hole’s activity is both unpredictable and dynamic.

“In our data, we saw constantly changing, bubbling brightness. Then, boom! A big burst suddenly appeared before fading again,” said lead author Farhad Yusef-Zadeh of Northwestern University. “Each observation brought new surprises.”

Unraveling the Cause: Turbulence and Magnetic Reconnection Drive Black Hole Flares

Researchers suggest two different mechanisms might be fueling this activity. Smaller flares likely result from turbulence within the accretion disk, where hot, magnetized gas compresses and releases brief bursts of radiation—similar to how the Sun produces solar flares. Meanwhile, larger flares may stem from magnetic reconnection events, where colliding magnetic fields generate bright explosions of particles traveling near the speed of light.

Interestingly, flares observed in two near-infrared wavelengths brightened and dimmed at slightly different times. Shorter-wavelength events peaked slightly before longer-wavelength ones, with delays ranging from a few seconds to 40 seconds. This pattern suggests that particles in the flares lose energy more quickly at shorter wavelengths, aligning with what scientists expect in a cosmic synchrotron, where charged particles spiral along magnetic field lines.

To refine their understanding, researchers hope to secure additional JWST observation time. Longer monitoring sessions would help reduce observational noise, allowing them to uncover finer details and determine whether these flares follow a repeatable pattern or occur randomly.

“When studying such weak flaring events, noise is a major challenge,” Yusef-Zadeh explained. “If we can observe for 24 hours straight, we’ll get a much clearer picture. That would be amazing.”

Read Original Article: Science Alert

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