http://www.newscientist.com/article.ns?id=dn8067
Massive young galaxy surprises astronomers
a.. 16:57 28 September 2005
b.. NewScientist.com news service
Enlarge image
A massive galaxy has been discovered early in the history of the universe, a
time when such mature galaxies were not thought to exist. The find calls into
question current thinking on galaxy formation.

The galaxy, HUDF-JD2, is one of the most distant ever observed. Its light,
captured by the Hubble and Spitzer space telescopes, began its journey towards
Earth a mere 800 million years after the Big Bang.

"That's a very short timescale to form such a massive galaxy," says Bahram
Mobasher, an astronomer with the European Space Agency and the Space Telescope
Science Institute in Baltimore, Maryland, US.

The time when stars and galaxies first formed is "a holy grail that many people
are hunting for in astronomy," says John Huchra, an astronomer with the
Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, US.

Similar galaxies have been seen at slightly shorter distances away, but none is
as massive as the latest find, which is about eight times the mass of our own
galaxy, the Milky Way.

Little and large
In the 1960s, astronomers suspected that big galaxies formed before small ones
as gravity clumped gas and dust together in a short span of time. Then theorists
proposed that small galaxies formed first and clumped together to form large
galaxies. If so, the bigger galaxies would have required a long time to
accumulate.

But the new observations of HUDF-JD2 suggest at least some large galaxies may
have formed first. To bolster the idea, Mobasher's team is now looking for more
galaxies at this distance or even further away and more massive.

Astronomers found the galaxy hiding among 10,000 other galaxies in the Hubble
Ultra Deep Field. This is the product of an intense look at a small patch of the
sky and is a composite of images in the visible and infrared ranges.

HUDF-JD2 cannot be seen in the visible range as this light has been absorbed by
hydrogen in the universe between it and Earth. But the galaxy could be seen in
longer wavelengths. It was unveiled by infrared and near infrared observations
by Hubble, and later by the Spitzer space telescopes and the Very Large
Telescope at the European Southern Observatory.

Scientists would normally confirm the distance of a galaxy using Earth-bound
telescopes, including the 10-metre Keck and 8-metre Gemini telescopes, but the
light is too faint.

However, the James Webb Space Telescope, currently scheduled for a launch no
earlier than 2013, should be able to confirm the distance because it will
measure in the near infrared.

The research on HUDF-JD2 will be published in a future issue of the
Astrophysical Journal.

Forwarded by yours Dr.BHUDIA-Science Group Of INDIA.
http://uk.groups.yahoo.com/group/venustransit_2004/
President:"Kutch Science Foundation".
Founder :"Kutch Amateurs Astronomers Club - Bhuj - Kutch".
Life Member:"kutch Itihaas Parishad".
kutchscience@..., kutchscience@...,
http://uk.geocities.com/wildlifeofkutch/


http://www.geocities.com/kutchscience
http://profiles.yahoo.com/kutchscience2000
http://in.groups.yahoo.com/group/scienceclubofindia
http://in.groups.yahoo.com/group/kutchscience
http://in.groups.yahoo.com/group/kachchh
http://in.groups.yahoo.com/group/bhuj

Do visit our ABOVE Clubs/Groups of Science club of India, Science
Group of India.



[Non-text portions of this message have been removed]