Black holes are intergalactic

Cambridge scientists have found dramatic new evidence that black holes are far more powerful than was previously thought: their impact reaches across enormous distances by heating up the gas spread between galaxies. This heating effect helps keep our galaxies the size they are. Stars form when gases cool, so by keeping the gas warmer, black holes stifle the formation of new stars.

“It is as if a heat source the size of a fingernail heats up a region the size of Earth,” explained Professor Andrew Fabian of the University of Cambridge, and lead author of a report on this research which will appear in an upcoming issue of ‘Monthly Notices of the Royal Astronomical Society’.

The scientists made the findings by analysing data from NASA’s Chandra X-ray Observatory which is currently orbiting the Earth (launched by Space Shuttle Columbia in 1999). They spotted energetic plumes of particles extending an astonishing 300,000 light years into a massive cluster of galaxies. The plumes are believed to emanate from huge vents of particles exploding from the area around a supermassive black hole, a massive reaction to when objects fall into the black hole. This provides clear new evidence that the influence of a black hole can reach over intergalactic distances.

Fabian’s group discovered the plumes by studying data from 280 hours (more than 1 million seconds) of Chandra observations of the Perseus cluster of galaxies. It is the longest X-ray observation ever taken of a galaxy cluster.

"The plumes show that the black hole has been venting for at least 100 million years, and probably much longer," said co-author Dr Jeremy Sanders, also of the University of Cambridge. “The venting process has slowed the growth of the central galaxy in the cluster, NGC 1275, which is one of the largest galaxies in the Universe.”

“Until 1970 people thought that stars were the most influential elements in the universe. This study is part of a growing realisation that sometimes black holes dominate far more than stars: in fact they have the power to stifle the formation of stars,” said Professor Fabian.