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When a black hole breaks all the rules

A composite image shows powerful radio jets from the supermassive black hole at the center of a galaxy in the Phoenix Cluster inflating huge "bubbles" in the hot, ionized gas surrounding the galaxy. The cavities inside the blue region were imaged by NASA's Chandra X-ray observatory. MIT

Black holes are supposed to act as a kind of thermostat at the center of a galaxy, warming up drifting gases just enough to regulate the creation of stars. But in one galaxy about 5.7 billion light years from Earth, the climate control system appears to be on the fritz.

A group including MIT scientists recently announced that they might have an answer to why the distant black hole is allowing about 1,000 stars per year to form in its neighborhood at the center of the Phoenix cluster — vastly outpacing most other galaxies.

The answer could help scientists better understand the relationships between galaxies and black holes across the universe.


“It’s an extreme system that doesn’t seem to follow all the rules that we’ve found, so it gives us a clue to what the rules are,” Michael McDonald, assistant professor of physics in MIT’s Kavli Institute for Astrophysics and Space Research, said in an interview.

In a paper co-authored by scientists from institutions including Cambridge University and the Harvard-Smithsonian Center for Astrophysics, McDonald and his colleagues said the potency of that galaxy has something to do with the unique way it expels gas.

Black holes suck in matter and spit out streams of 10-million-degree material, which usually pushes away colder gas that would otherwise condense to form stars. .

But in the center of the Phoenix cluster, those hot streams are allowing the cold gas to form bubbles, leading to an abundance of new stars, the researchers believe..

The researchers published their findings Feb. 14 in the Astrophysical Journal.

McDonald said one potential explanation is that the black hole may be relatively small, and not powerful enough to do the job that others carry out.

“It’d be like putting a civilian in the ring with Mike Tyson,” McDonald said in an MIT news release. “It’s just not up to the task of blowing this cold gas far enough away that it would never come back.”


Andy Rosen can be reached at andrew.rosen@globe.com. Follow him on Twitter at @andyrosen.