ALMA Finally Catches the Milky Way's Black Hole “Breathing”

Republished from ALMA, the Atacama Large Millimeter/submillimeter Array, where it first appeared as a press release on 2026-06-04. ALMA press-release texts and images are released under the Creative Commons Attribution 4.0 International licence; the text is reproduced here unchanged apart from formatting. Credit: ALMA. Read the original for the latest version and any updates.

By creating the most detailed map ever of cold gas around Sagittarius A*, astronomers have provided compelling evidence for a long-sought black-hole wind

Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) have finally found clear evidence that the supermassive black hole at the center of the Milky Way, Sagittarius A*(Sgr A*), is blowing a hot cosmic wind – something scientists have been hunting for over 50 years. Astronomical theory says that when a black hole feeds on gas, it should also blow some material back out as winds or jets. Until now, the wind coming from our own Galaxy’s black hole had never been seen clearly. Using several years of highly detailed ALMA observations, astronomers mapped cold gas within just a few light‑years of Sgr A*. After carefully removing the black hole’s bright radio glow, they uncovered a giant, cone‑shaped hole in the cold gas, pointing straight at the black hole – the unmistakable imprint of a large, hot, active wind launched from Sgr A*.

With over five years of ALMA observations (made at a wavelength of 1.3 millimeters) astronomers mapped emission from carbon monoxide (CO) molecules, a classic tracer of cold molecular gas, within only about three light‑years of Sgr A*. By carefully modeling and subtracting the black hole’s own rapidly varying radio emission, they were able to reveal extremely faint, intricate structures in the surrounding gas. Data from NASA’s Chandra X-Ray Observatory show hot gas filling the same region, confirming that this is a black hole–powered outflow, not something caused by nearby stars.

The resulting map is roughly 100 times more sensitive and 80 times higher in angular resolution than previous CO maps of the region, making it the most sensitive, highest‑resolution map of cold gas within three light‑years of Sgr A* ever obtained. This discovery relied not only on years of ALMA observations but also innovative data‑processing techniques to model and subtract Sgr A*’s rapidly variable emission, revealing fainter structures in the surrounding gas.

The team estimates this wind has been blowing for at least 20,000 years, but it’s relatively gentle compared to the dramatic jets seen in other galaxies. By revealing this long‑sought wind, ALMA (and Chandra) have helped solve a decades‑old mystery and given scientists their clearest view yet of how a supermassive black hole can both feed on and reshape its surroundings at the heart of our Milky Way Galaxy.