Rapidly spinning black holes might be source of jets that affect galaxy growth

Washington, Jan 11 : A new study, using results from NASA's Chandra X-ray Observatory, has provided evidence that many supermassive black holes are spinning extremely rapidly, causing the formation of powerful jets that affect galaxy growth by pumping huge amounts of energy into their environment.

For the study, a team of scientists compared leading theories of jets produced by rotating supermassive black holes with Chandra data.

After sampling nine giant galaxies that exhibit large disturbances in their gaseous atmospheres, researchers came up with the supposition that the central black holes in these galaxies must be spinning at near their maximum rates.

"We think these monster black holes are spinning close to the limit set by Einstein's theory of relativity, which means that they can drag material around them at close to the speed of light," said Rodrigo Nemmen, lead author of a paper on the new results.

According to Einstein's theory, a rapidly spinning black hole makes space itself rotate. This effect, coupled with gas spiraling toward the black hole, can produce a rotating, tightly wound vertical tower of magnetic field that flings a large fraction of the inflowing gas away from the vicinity of the black hole in an energetic, high-speed jet.

"Extremely fast spin might be very common for large black holes," said co-investigator Richard Bower of Durham University. "This might help us explain the source of these incredible jets that we see stretching for enormous distances across space," he added.

Computer simulations by other authors have suggested that black holes may acquire their rapid spins when galaxies merge, and through the accretion of gas from their surroundings.

One significant consequence of powerful, black-hole jets in galaxies in the centers of galaxy clusters is that they can pump enormous amounts of energy into their environments, and heat the gas around them.

This heating prevents the gas from cooling, and affects the rate at which new stars form, thereby limiting the size of the central galaxy.

Therefore, understanding the details of this fundamental feedback loop between supermassive black holes and the formation of the most massive galaxies remains an important goal in astrophysics.

ANI