Supermassive black hole `discovered` in dwarf galaxy

Astronomers have discovered a supermassive black hole in a nearby dwarf galaxy - Henize 2-10.

Last Updated: Jan 10, 2011, 17:54 PM IST

Washington: 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
a million times more massive than the sun in a star-forming
dwarf galaxy is a strong indication that supermassive black
holes formed before the buildup 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 `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
center 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.

PTI