Chandra Helps Find Missing Wind from Milky Way's Black Hole
Sagittarius A*
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Credit: X-ray: NASA/CXC/Northwestern Univ./M. Gorski; Radio:ESO/NAOJ/NRAO/ALMA;
Image Processing: NASA/CXC/SAO/N. Wolk
Astronomers have found that the supermassive black hole at the center of the Milky Way, known as Sagittarius A*(Sgr A*), is blowing a hot cosmic wind — something scientists have been hunting for over 50 years.
This composite image shows the evidence for the wind blowing away from Sgr A*. The white dot in the center of the image shows Sgr A*. In orange is data from the Atacama Large Millimeter/Submillimeter Array (ALMA) radio telescopes in Chile, mapping the location of cold gas composed of carbon monoxide in the image. In blue is X-ray data from NASA’s Chandra X-ray Observatory. A large cone-shaped cavity, visible as an absence of cold gas in the ALMA data, is filled by hot X-ray-emitting gas in the Chandra data. Researchers think a hot, energetic wind blowing from Sgr A* created this structure by sweeping the cold gas away or heating it up.
Credit: X-ray: NASA/CXC/UMass/D. Wang et al.; Radio: ALMA (ESO/NAOJ/NRAO)/S. Longmore et al.; Background: ESO/D. Minniti et al.
Theory says that when a black hole feeds on gas, it should also blow some material away 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*.
A paper by Mark Gorski and Lena Murchikova (Northwestern University) describing these results has been accepted in The Astrophysical Journal Letters. NASA's Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program. The Smithsonian Astrophysical Observatory's Chandra X-ray Center controls science operations from Cambridge, Massachusetts, and flight operations from Burlington, Massachusetts.