- A decades-long search has revealed signs of a subtle outflow from the Milky Way’s central black hole.
- Researchers say they have finally found the outflow, shedding new light on the behavior of the Milky Way’s mysterious centerpiece.
- Mark Gorski, who co-led the study, stated, "Unless a black hole exists in a perfect vacuum, it must blow a wind somehow."
- With new observations, this is the first time we’ve had a clean enough view to see the wind’s imprint.
- The researchers found a large cone-shaped cavity, nearly one parsec long and spanning 45 degrees, that contained no cold molecular gas.
- They concluded that the most likely explanation was a hot wind originating from Sgr A*.
- Based on the extent of the wind’s influence on a nearby stream of ionized gas, the team estimates that the outflow has been active for at least 20,000 years.
A decades-long search has finally yielded results as astronomers have uncovered a subtle outflow from the Milky Way's central black hole, Sgr A*. Researchers utilized five years of observations from the Atacama Large Millimeter/Submillimeter Array (ALMA) in Chile to produce the most detailed image yet of the cold molecular gas surrounding Sgr A*.1
The study, co-led by Northwestern's Mark Gorski, revealed a large cone-shaped cavity nearly one parsec (about three light-years) long, which contained no cold molecular gas. Gorski noted, “Unless a black hole exists in a perfect vacuum, it must blow a wind somehow.” This finding suggests that a hot wind is emanating from Sgr A*, which has been active for at least 20,000 years.356
The researchers calculated that the energy required to create this cavity exceeds what can be provided by the stars in that area. They observed that the wind is not powerful and its direction likely changes over time. This breakthrough provides a clearer understanding of the behavior of the Milky Way's mysterious centerpiece, marking a significant advancement in astrophysical research.
Gorski emphasized the importance of these observations, stating, “With new observations, this is the first time we’ve had a clean enough view to see the wind’s imprint.”4
“Researchers have found signs of a subtle outflow from the Milky Way's central black hole, Sgr A*. This discovery, based on five years of observations, sheds light on the black hole's influence on its surroundings.”
