Nearest galaxy powered by two black holes: Astronomers

Astronomers using NASA's Hubble telescope have found that the nearest galaxy to Earth that hosts a quasar is powered by two central black holes furiously whirling about each other.

The finding suggests that quasars - the brilliant cores of active galaxies - may commonly host two central supermassive black holes, which fall into orbit about one another as a result of the merger between two galaxies.

Like a pair of whirling skaters, the black-hole duo generates tremendous amounts of energy that makes the core of the host galaxy outshine the glow of its population of billions of stars, which scientists then identify as quasars.

Scientists looked at the observations of ultraviolet radiation emitted from the center of Markarian 231 (Mrk 231) to discover what they describe as "extreme and surprising properties."

Mrk 231 is located 600 million light-years away.

"We are excited about this finding because it not only shows the existence of a close binary black hole in Mrk 231 but also paves a new way to systematically search binary black holes via the nature of their ultraviolet light emission," explained Youjun Lu from National Astronomical Observatories of China at Chinese Academy of Sciences.

The central black hole is estimated to be 150 million times the mass of our Sun and the companion weighs in at four million solar masses.

The dynamic duo completes an orbit around each other every 1.2 years.

"The structure of our universe, such as those giant galaxies and clusters of galaxies, grows by merging smaller systems into larger ones, and binary black holes are natural consequences of these mergers of galaxies," added co-investigator Xinyu Dai from University of Oklahoma.

The binary black holes are predicted to spiral together and collide within a few hundred thousand years.

The results were published in the Astrophysical Journal.