Black Hole "Hearts" Warm Galaxies, Control Growth

Ker Than for National Geographic News
November 21, 2008

A colossal black hole nestled in the center of a distant galaxy controls its own growth and the growth of surrounding stars by pumping out energy at regular intervals, a new study says.

"It looks like a beating heart," said study team member Mateusz Ruszkowski, an astronomer at the University of Michigan.

The black hole resides in the center of the elliptical galaxy M84, 55 million light-years from Earth.

New images from NASA's Chandra X-Ray Observatory reveal that with every beat, the black hole shoots twin jets of superheated gas, or plasma, into the galaxy.

The plasma jets warm the cool gas around them, creating bubbles of hot gas that swell until they are several thousand light-years across.

As the bubbles form they create a "Russian doll" effect, in which one bubble is nested inside a larger one, Ruszkowski said.

Because the bubbles grow at a constant rate, the team determined the age of each bubble, revealing that the black hole pumps out energy once every ten million years.

Scientists knew that black holes could eject energy in rare and violent outbursts, but the new finding is the first direct evidence that they are also capable of gentler and more consistent discharges.

"Just like our hearts periodically pump our circulatory systems to keep us alive, black holes give galaxies a vital warm component," study co-author Alexis Finoguenov of the Max-Planck Institute for Extraterrestrial Physics in Germany, said in a statement.

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