The monster black hole that anchors our galaxy is safely 28,000 light years away from Earth. That’s a good thing, too. The region around that back hole is overflowing with dangerous radiation and fragmented stars. Astronomers observing the center of the Milky Way have spotted some unusual features that drive home just how violent the area is. The galaxy sports a pair of gargantuan “X-ray chimneys” that expel the matter and energy building up around the black hole.
UCLA professor of astronomy and astrophysics Mark Morris, who contributed to the research, likens the features to exhaust vents, bleeding off energy from the galaxy in the form of X-rays. The international team looked to the black hole, known as Sagittarius A* (pronounced “Sagittarius A Star”) in an effort to learn more about star formation in the Milky Way. All galaxies foster the development of stars, but the rate of new star formation can vary wildly. The fate of the matter and energy spiraling toward a galaxy’s central black hole can be a significant factor in star formation.
To track the material blasted out around Sagittarius A*, the researchers turned to the European Space Agency’s XMM-Newton satellite. This X-ray observatory launched almost 20 years ago, but it’s still going strong. The team used data from 2012, as well as 2016 to 2018 to see what the black hole was doing with all the stars getting smashed to bits in its general vicinity.
According to the researchers, Sagittarius A* produces “chimneys” of X-ray that extend north and south from the disk of the galaxy. The structures are more appropriately known as Fermi bubbles, massive cavities carved out of the gas cloud surrounding the galaxy. The north and south chimney both start within 160 light years of the black hole, extending outward about 25,000 light years. That’s almost the distance from Sagittarius A* to Earth.
The black hole in our galaxy is about 4 million times the size of the sun, but other galaxies have central black holes that are much larger. We can study the Milky Way close up, which could provide insights into how these more energetic galaxies work. Understanding how energy moves through the chimneys and into surrounding space could help explain why some regions become rich in star formation, and others are relatively barren.