Michigan State University (MSU) researchers have made groundbreaking discoveries about the supermassive black hole at the center of the Milky Way, known as Sagittarius A* (Sgr A*).
The use of X-ray data over the last ten years NASA’s NuSTAR telescopethese findings provide new insight into the mysterious environment surrounding this colossal cosmic entity.
Discovering hidden flares and echoes
Grace Sanger-Johnson, a post-baccalaureate researcher at MSU, discovered nine earlier undetected X-ray flashes of A* scorer by careful analysis of ten years of data. These flares are high-energy discharges that illuminate the immediate vicinity of a black hole, a region typically shrouded in darkness due to the immense gravitational force from which even light cannot escape.
“We have a front-row seat to observe this unique cosmic fireworks display at the center of our own Milky Way galaxy,” said Shuo Zhang, a Sanger-Johnson advisor. The flashes provide a rare opportunity to study the surroundings of a black hole and better understand the extreme conditions that exist there.
While Sanger-Johnson focused on flareJack Uteg, an undergraduate researcher in the MSU Honors College, studied X-ray echoes from a nearby molecular cloud known as “The Bridge.” These echoes offer insight into the activity of Sgr A* in past centuries.
By examining nearly 20 years of data from NuSTAR and European Space Agency X-ray Multimirror (XMM) Newton’s Uteg observatory found that the cloud’s brightness is likely a delayed reflection of past X-ray bursts Black hole.
“The brightness we see is most likely a delayed reflection of past X-ray bursts from Sgr A*,” explained Uteg. This analysis helps to reconstruct a timeline of the black hole’s past behavior and reveals that Sgr A* was significantly more active about 200 years ago.
The significance of these findings
These discoveries are crucial to understanding the dynamic environment at the heart of our galaxy. Black holes they are notoriously difficult to study directly due to their intense gravitational fields that distort light and other signals.
However, by examining the effects of these fields on the surrounding matter, scientists can infer important details Black hole activity. The work of Sanger-Johnson and Utega exemplifies this approach, shedding light on both the immediate and historical behavior of Sgr A*.
“Grace and Jack’s contributions are a source of immense pride,” said Shuo Zhang, assistant professor in MSU’s Department of Physics and Astronomy. “Their work exemplifies MSU’s commitment to pioneering research and supporting the next generation of astronomers. This research is a prime example of how MSU scientists are unraveling the mysteries of the universe and bringing us closer to understanding the nature of black holes and the dynamic environment at the heart.” our galaxy.”
Understanding black hole flares
The newly discovered eruptions are dramatic bursts of high-energy light that occur at Black hole absorbs material such as gas clouds or stars. These eruptions provide valuable data on the physical conditions near the event horizon, the boundary beyond which nothing can escape the black hole’s gravity. When Black hole consumes matter, the material heats to extreme temperatures as it accelerates and spirals inward, emitting intense X-rays and other radiation in the process. This radiation is what scientists observe as a flare.
Flare they are usually short, lasting from a few minutes to a few hours, but during that time they can release enormous amounts of energy. The energy output of these eruptions can be equivalent to the energy output of millions of suns. The Sanger-Johnson analysis, which involved sifting through data from 2015 to 2024, revealed the characteristics of these outbreaks, helping to build a comprehensive database for future research. Every flare it provides a snapshot of the dynamical processes taking place in the vicinity of a black hole and offers clues about the behavior of accreting material and the physics of the extreme environment.
“We hope that by creating this data bank of Sgr A* flares, we and other astronomers can analyze the properties of these X-ray flares and infer the physical conditions in the extreme environment of a supermassive black hole,” Sanger-Johnson said. By studying the timing, intensity and frequency of these flares, scientists can infer details about the rate at which the black hole consumes material and the nature of the surrounding accretion disk. This information is key to developing models of black hole growth and activity.
