Intermediate-mass black hole detected

National Geographic : A new, middleweight black hole has been verified. Until now only two types—small stellar (several times heavier than the Sun) and supermassive (equivalent to many million Suns)—were thought to exist. However, while studying a star cluster some 300 million light-years away, astronomers with NASA’s Chandra X-Ray Observatory and Swift spacecraft discovered HLX-1, which has the matter of about 90 000 Suns. Intermediate-mass black holes may have been formed by the breakdown of very massive stars, according to Natalie Webb of the Research Institute in Astrophysics and Planetology in France and lead author of a paper published today in Science. The intermediates may also be the progenitors of supermassive black holes in either of two ways: A single intermediate accumulates enough matter to grow into a supermassive, or a number of intermediates merge. Astronomers are still working to figure out how common intermediate-weight black holes are in the universe.