AGN Feed in Distant GalaxiesAstronomers usually try to educate the public that black holes do not go around actively eating the hearts out of galaxies. Usually. On July 24, astronomers announced that in the early days of the universe large numbers of young supermassive black holes actually spent their days feeding on galaxy cores. (image credit: NASA/CXC/Ohio State Univ./J.Eastman et al.)

“The black holes in these early [galaxy] clusters are like piranha in a very well-fed aquarium,” said Jason Eastman of the Ohio State University and first author of this study.

While there are some feeding supermassive black holes (technically called Active Galactic Nuclei or AGN) in the modern universe, they are rare. Using the Chandra X-ray Observatory, Eastman’s team found that when the universe was 8 billion years old there were 20 times more AGN than there were when it was 11.2 billion years old. Today, the universe is 13.7 billion years old and there are no nearby AGN.

In the early universe, galaxies were rich in dust and gas that could be used to form stars or to feed AGN. When the AGN gobble the dust and gas, they often burp out high-energy jets and expel blasts of X-rays that stifle star formation, leaving galaxies devoid of stellar nurseries.