Article Posted on : - Jan 10, 2011

The dwarf galaxy Henize 2-10.

WASHINGTON (PTI): Astronomers have discovered a supermassive black hole in a nearby dwarf galaxy which they claim will shed light on how black holes and galaxies may have grown in the early history of the Universe.

A team in the US says that finding a black hole million times more massive than the Sun in a star-forming dwarf galaxy is a strong indication that supermassive black holes formed before the build-up of galaxies.

The galaxy, called Henize 2-10, 30 million light years from Earth, has been studied for years, and is forming stars very rapidly, the journal Nature reported.

"This galaxy gives us important clues about a very early phase of galaxy evolution that has not been observed before," said lead astronomer Amy Reines of the University of Virginia.

Reines added: "Now, we have found a dwarf galaxy with no bulge at all, yet it has a supermassive black hole. This greatly strengthens the case for the black holes developing first, before the galaxy's bulge is formed."

The scientists, in fact, found a region near the centre of the galaxy that strongly emits radio waves with characteristics of those emitted by superfast "jets" of material spewed outward from areas close to a black hole.

They then searched images from the Chandra X-Ray Observatory that showed this same, radio-bright region to be strongly emitting energetic X-rays. This combination indicates an active, black-hole-powered, galactic nucleus, they say.

Henize 2-10 differs not only in its irregular shape and small size but also in its furious star formation, concentrated in numerous, very dense "super star clusters".

"This galaxy probably resembles those in the very young Universe, when galaxies were just starting to form and were colliding frequently. All its properties, including the supermassive black hole, are giving us important new clues about how these black holes and galaxies formed at that time," Kelsey Johnson, team member, said.