Massive Black Hole Located 6.1 Billion light-years Away Spinning at Nearly Half the Speed of Light

Giant black hole located some six billion light years from Earth is spinning at roughly half the speed of light. The study could help astronomers understand the evolution of black holes.

"It is spinning like a top, very rapidly," says co-author Mark Reynolds of the University of Michigan, Ann Arbor, National Geographic reports.

Estimating the mass of a black hole is a relatively easier task than measuring its spin, astronomers said. Methods used to determine the spin of a black hole rely on several steps. Previously, astronomers had estimated spin rates of black holes located some 2.5 billion and 4.7 billion light-years away. This is the first time that researchers have been able to directly measure spin rate of a black hole located 6.1 billion years away.

Astronomers used NASA's Chandra X-ray Observatory and the European Space Agency's (ESA's) XMM-Newton to study the black hole. Their research is published in the journal Nature.

Twisted Space and Giant Gravitational Lenses

The massive black hole is pulling in surrounding gas and producing a quasar known as RX J1131-1231 (RX J1131 for short), NASA said in a news release.

Quasars or "qausi-stellar radio sources" are the bright centers of very distant galaxies.

Luckily for astronomers, a giant elliptical galaxy along the line of sight to the quasar acted as a large lens in space, magnifying light from the quasar.

Gravitational lensing helps astronomers study the minute details of a quasar. Read more about the lens, here.

"Because of this gravitational lens, we were able to get very detailed information on the X-ray spectrum - that is, the amount of X-rays seen at different energies - from RX J1131," said  Reynolds . "This in turn allowed us to get a very accurate value for how fast the black hole is spinning."

According to NASA, X-rays are produced when "swirling accretion disk of gas and dust" around the black hole forms a corona. X rays from the corona reflect off from the disk. The edge of the black hole changes the X-ray spectrum due to its massive gravitational force. Large changes in the X-ray spectrum mean that the inner edge of the disk is closer to the black hole.

"We estimate that the X-rays are coming from a region in the disk located only about three times the radius of the event horizon, the point of no return for infalling matter," said Jon M. Miller of Michigan, another author on the paper. "The black hole must be spinning extremely rapidly to allow a disk to survive at such a small radius."

A spinning black hole drags space around it, which leads to the matter orbiting closer to the black hole.

The present study gave researchers important clues about the growth and development of black holes.

The black hole in RX J1131, spinning at half the speed of light, shows that it grew from mergers rather than by accumulating material.