Powerful jets streaming out of giant black holes can blow away the usual star-forming fuel in a galaxy, astronomers have discovered, creating what they've dubbed "red and dead" galaxies full of old reddish stars yet possessing almost none of the hydrogen gas needed to create new ones.
However, the black hole doesn't need to be all that powerful, they've now discovered from observations of a nearby galaxy home to a somewhat modest black hole at its center.
Using the Atacama Large Millimeter/submillimeter Array (ALMA) telescope in Chile, they've observed turbulence in its star-forming fuel, a "perfect storm" that is suppressing the formation of stars in what should otherwise be a model star factory.
The turbulence is caused as the jets exploding from the black hole in the center of the galaxy NGC 1266 collide with an extraordinarily dense surrounding gas envelope that may have resulted from a recent merging with a smaller galaxy, the scientists say.
The gas is so dense it is blocking almost 98 percent of the material in the black hole's jets, keeping it from escaping out of the galactic center, they report.
"Like an unstoppable force meeting an immovable object, the particles in these jets meet so much resistance when they hit the surrounding dense gas that they are almost completely stopped in their tracks," says Katherine Alatalo at the California Institute of Technology in Pasadena.
The result is the extreme turbulence throughout the surrounding envelope of gas, causing disruption in the critical first stages of star formation.
"So what we see is the most intense suppression of star formation ever observed," Alatalo says.
The galactic region contains an amount of star-farming gas around 400 million times the mass of our own Sun, and gas at these concentrations should be forming stars at a rate 50 times greater than is being observed in NGC 1266, the researchers say.
Previously, astronomers had thought only extremely powerful black holes created jets with enough energy to serve as an "off switch" switch for star formation.
"The usual assumption in the past has been that the jets needed to be powerful enough to eject the gas from the galaxy completely in order to be effective at stopping star formation," says National Radio Astronomy Observatory astronomer Mark Lacy.
The ALMA observations suggest NGC 1266 is probably choking on its own star-making fuel, seeming to defy the rules of normal star formation, the researchers say.
That's the result of the black hole's jets creating turbulence in the gas, keeping it from settling down and collapsing, effectively "quenching" the birth of any new stars, Lacy says.
NGC 1266, located around 100 million light-years away in the constellation Eridanus, is a spiral galaxy similar to our own Milky Way.
