July 1, 2009

Astronomers find new kind of black hole

An international team of astronomers using the European Space Agency's XMM-Newton X-ray observatory says it's discovered a new kind of black hole.

The scientists, led by Sean Farrell of the University of Leicester, England, said the newly found black hole weighs more than 500 solar masses and is a missing link between lighter stellar-mass and heavier super-massive black holes.

Stellar-mass black holes about 3 to 20 times as massive as the sun, and super-massive black holes several million to several thousand million times as massive as the sun, have long been known to exist. Because of the large gap between the two extremes, scientists have speculated the existence of a third, intermediate class of black holes, with masses between a hundred thousand and several hundred thousand solar masses.

Up until now, scientists were unable to confirm that this elusive intermediate class actually existed. Farrell's team was analyzing data obtained by XMM-Newton for neutron stars and white dwarves, when they stumbled upon the black hole.

Called HLX-1, it is located approximately 290 million light years from Earth.

The discovery will be detailed in the July 2 edition of the journal Nature.