London, July 6 (Inditop.com) Astronomers have come by the first solid evidence of a new class of medium sized black holes, with more than 500 times the sun’s mass, in a distant galaxy.

This new source, identified as HLX-1 (Hyper-Luminous X-ray source 1), lies towards the edge of the galaxy ESO 243-49. It is ultra-luminous in X-rays, with 260 million times the brightness of the Sun.

Until now, identified black holes have been either super-massive (several million to several billion times the mass of the sun) in the centre of galaxies or about the size of a typical star (between three and 20 solar masses).

The team, led by astrophysicists at the Centre d’Etude Spatiale des Rayonnements in

France, detected the new black hole approximately 290 million light years from Earth with the European Space Agency’s XMM-Newton X-ray space telescope.

A black hole is an object with such a powerful gravitational field so dense that it absorbs all the light that passes near it and reflects nothing.

It had been long believed by astrophysicists that there might be a third, intermediate class of black holes, with masses between a hundred and several hundred thousand times that of the Sun. However, such black holes had not been reliably detected until now.

“While it is widely accepted that stellar mass black holes are created during the death throes of massive stars, it is still unknown how super-massive black holes are formed,” said Sean Farrell, who works at the University of Leicester, Britian.

“One theory is that super-massive black holes may be formed by the merger of a number of intermediate mass black holes. To ratify such a theory, however, you must first prove the existence of intermediate black holes,” Farrell was quoted as saying in a Centre d’Etude release.

“The identification of HLX-1 is therefore an important step towards a better understanding of the formation of the super-massive black holes that exist at the centre of the Milky Way and other galaxies,” he added.

These findings were published in Nature