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Constant Activity Surrounds Milky Way’s Supermassive Black Hole

At the core of our Milky Way galaxy, the supermassive black hole known as Sagittarius A*, or Sgr A*, is far from dormant. Recent observations have unveiled that the ring of plasma enveloping this cosmic giant exhibits a dynamic and vibrant nature, consistently flickering and producing intense bursts of energy.

Utilizing the advanced capabilities of the James Webb Space Telescope (JWST), astronomers conducted extensive observations of Sgr A* and its surrounding accretion disk over the course of a year, from April 2023 to April 2024. This marked the first instance of such prolonged and detailed monitoring of the central black hole in our galaxy.

According to astrophysicist Farhad Yusef-Zadeh of Northwestern University, the data reveals a “constant bubbling” pattern in the emitted light from the disk, with changes occurring every few seconds to minutes. The team noted that several times a day, seemingly at random intervals, the disk would unleash a remarkably bright flare, as documented in their Feb. 20 report in the journal Astrophysical Journal Letters.

Sgr A* boasts a mass roughly 4 million times that of the sun and resides approximately 26,000 light-years away from Earth. While it is generally subdued, occasionally consuming nearby material and emitting energy, ongoing research has indicated that the plasma disk is characteristically flickering. Previous studies, including the initial images of this black hole, hinted at the disk’s dynamic nature, while computer models predicted that brightness fluctuations could range from mere minutes to years. The recent findings not only validate these theories but also provide deeper insights into the mechanisms of the flickering phenomena.

The JWST’s positioning, beyond Earth’s orbit, grants it the unique ability to capture uninterrupted data, facilitating extensive observational periods. Furthermore, it can analyze astronomical objects in two different wavelengths at once, enhancing the depth of information obtained.

“With this capability, we can observe in color instead of just in black-and-white,” said Yusef-Zadeh.

The research team hypothesizes that two distinct processes contribute to the observed variations. The turbulence within the accretion disk likely causes the subtle bubbling effects, while the explosive flares may relate to magnetic reconnection events, similar to those seen in solar activity, where colliding magnetic field lines release substantial energy.

To further investigate these phenomena, the team has requested an uninterrupted 24-hour observation period with the JWST.

Source
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