Maltese astronomer discovers unusual black hole

'It is effectively the smallest galaxy in which there is a super-massive black hole' - Victor Debattista, University of Washington

A team led by Maltese astronomer Victor Debattista has made a discovery that might help students of the skies understand small galaxies better.

The six-member team found evidence of a black hole at the heart of a dwarf elliptical galaxy - the second time a super-massive black hole was found in such a small galaxy.

Black holes - whose gravitational fields are so powerful that nothing, not even light, can escape - are found at the centre of many galaxies.

Speaking to The Times from his home in Seattle, Washington state, Dr Debattista, a postdoctoral researcher in astronomy at the University of Washington, explained that it was previously thought such small galaxies would not be able to have a black hole.

He explained that the galaxy - called VCC128 - is one per cent the size of the Milky Way, where earth is, and 54 million light years away from it. The finding came about when the team started sifting through archived data from the Hubble Space Telescope.

"We were looking at dwarf galaxies - a collection of stars - and realised there were two nuclei. This was very unusual." When the team continued examining the images they realised that the two nuclei were very similar, which made them think they were a disk of stars surrounding a black hole.

"It is a very small galaxy on the outskirts of the cluster. It is effectively the smallest galaxy in which there is a super-massive black hole," he said.

"We want to understand how these black holes managed to get to this size," he said, adding that all of the galaxy's stars combined equal between 100 million and one billion of the earth's sun.

The team is interested in following up on the galaxy, Dr Debattista said.

The discovery was explained in a poster, of which Dr Debattista was lead author, presented at the American Astronomical Society's annual meeting in Seattle last week.