After five decades of extensive research, astronomers have discovered compelling evidence that Sagittarius A*, the supermassive black hole with 4.3 million solar masses at the heart of the Milky Way galaxy, is emitting hot cosmic winds. These winds are shaping a vast cavity close to the galaxy’s center.
This image illustrates the winds emanating from Sagittarius A*. The central white dot marks a supermassive black hole. The orange data from ALMA indicates the position of cold carbon monoxide gas, while the blue data from Chandra shows hot, X-ray-emitting gas. The large conical cavity represents a region devoid of cold gas with intense hot gas emissions. Image credits: NASA / CXC / UMass / Wang et al. / ALMA / ESO / National Astronomical Observatory of Japan / NRAO / Longmore et al. / Miniti et al.
Theoretical physics suggests that as black holes devour matter, they generate winds or jets. Even minimal amounts of gas falling into a black hole can produce enough energy to expel matter outward.
Until recent observations, the winds from Sagittarius A*, our galaxy’s central black hole, had never been distinctly identified.
Astronomers utilized years of detailed observations from the Atacama Large Millimeter/Submillimeter Array (ALMA) to analyze the cold gas within several light-years of the black hole.
By eliminating the bright radio emissions from the black hole, researchers unveiled a vast cone-shaped void in the cold gas, directly aligned with the black hole. This phenomenon serves as clear evidence of substantial, hot winds expelled from Sagittarius A*.
“Unless a black hole exists in a complete vacuum, some form of wind should be present,” stated Dr. Mark Gorsky, an astronomer at Northwestern University.
“However, there is no absolute vacuum in space.”
“These observations represent the first time we can distinctly identify wind signatures,” Dr. Gorsky added.
“As we analyzed the data, we realized, ‘This is it. This is what scientists have been searching for over the past 50 years.’”
Over five years, Dr. Gorski and colleague Dr. Lena Murchikova mapped radiation from carbon monoxide, a key indicator of cold molecular gases, within approximately 1 parsec (or 3 light-years) of Sagittarius A*.
The careful modeling and subtraction of the black hole’s rapidly varying radio emissions allowed researchers to discern faint and complex structures in the surrounding gas.
“For the first time, we’ve confirmed that a black hole is being fed molecular gas very close to it,” explained Dr. Murchikova from Northwestern University.
“The winds are moderate, and their direction may fluctuate over time.”
“This discovery indicates that our black hole is not an isolated phenomenon, nor is our position in the universe unique.”
Data from NASA’s Chandra X-ray Observatory confirmed the presence of hot gas in the same vicinity, verifying that this outflow was indeed from a black hole and not from a neighboring star.
“Exceptional claims necessitate exceptional evidence,” Dr. Gorski noted.
“We were cautious to ensure we weren’t misinterpreting an image artifact, and the X-ray images from Chandra corroborated our findings. The molecular signatures aligned perfectly.”
The ALMA map boasts approximately 100 times greater depth and 80 times sharper resolution than previous carbon monoxide images in the region, making it the most sensitive and highest-resolution map of cold gas surrounding Sagittarius A* to date.
Researchers estimate that these winds have been active for at least 20,000 years, though they are relatively calm in comparison to the dramatic jets observed in other galaxies.
“Most galaxies remain relatively dormant throughout their lifetimes,” Dr. Murchikova commented.
“However, we only observe them during these explosive episodes.”
“While it’s captivating to study black holes during these outburst phases, they represent a brief segment of their overall existence.”
“Sagittarius A* has finally opened a window into the life of this otherwise silent black hole.”
The team’s findings will be published in the Astrophysical Journal Letters.
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Mark D. Gorski and Lena Murchikova. 2026. Discovery of active winds from the central black hole of the Milky Way Galaxy. APJL 1004, L7; doi: 10.3847/2041-8213/ae63cf
Source: www.sci.news
