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Black Holes Encyclopedia

Stars and Black Holes Form Simultaneously in Early Galaxies

(From the July/August 2003 issue of StarDate magazine)

A giant cosmic lens has allowed astronomers to peer deeply into a quasar 12 billion light-years from Earth, giving them insight into the workings of the quasar’s host galaxy at a time when the universe was only 15 percent of its present age.

Quasar PSS J2322+1994 is too distant for the Very Large Array (VLA) radio telescope to study the details of its host galaxy under normal circumstances. A galaxy in between the quasar and Earth served as a gravitational lens, magnifying the quasar’s image and spreading it into a ring around the intervening galaxy, called an “Einstein ring.”

This close-up look allowed Chris Carilli of the National Radio Astronomy Observatory and his team to discern the presence of a rotating disk of carbon monoxide gas surrounding the quasar host galaxy’s core. Carbon monoxide gas is a marker of star formation in galaxies.

Studies of nearby galaxies have supported the idea that the same gas that feeds a galaxy’s central black hole also is the nursery for large numbers of forming stars. Until now, scientists didn’t know if this would apply to the galaxies forming in the very early universe.

“This unique look into a very distant, young galaxy gives us unprecedented insight into the processes that produced both tremendous numbers of stars and supermassive black holes in forming galaxies,” Carilli said. “This work strongly supports the idea that the stars and the black holes formed simultaneously.” -- Rebecca Johnson