Big Flop

HubbleSite - Release Text about "NASA Finds "Big Baby" Galaxies
in Newborn Universe"

NASA Press Release:
Sept. 27, 2005
Erica Hupp/George Deutsch
Headquarters, Washington
(Phone: 202/358-1237/1753)
Gay Hill
Jet Propulsion Laboratory, Pasadena, Calif.
(Phone: 818/354-0344)
Ray Villard
Space Telescope Science Institute, Baltimore
(Phone: 410/338-4514)
RELEASE: 05-286

NASA FINDS "BIG BABY" GALAXIES IN NEWBORN UNIVERSE

Two of NASA's Great Observatories, the Spitzer and Hubble Space
Telescopes, have teamed up to "weigh" the stars in several distant
galaxies. One of these galaxies, among the most distant ever seen,
appears to be unusually massive and mature for its place in the young
universe.

This came as a surprise to astronomers, as the earliest galaxies in
the universe are commonly thought to have been much smaller
associations of stars that gradually merged to build large galaxies
like our Milky Way.

"This galaxy, named HUDF-JD2, appears to have bulked up quickly,
within the first few hundred million years after the big bang. It
made about eight times more mass in stars than are found in our own
Milky Way, and then, just as suddenly, it stopped forming new stars,
"said Bahram Mobasher of the Space Telescope Science Institute,
Baltimore and the European Space Agency, Paris.

The galaxy was pinpointed among approximately 10,000 others in
a small patch of sky called the Hubble Ultra Deep Field (UDF).
The galaxy is believed to be about as far away as the most distant
known galaxies. It represents an era when the universe was only
800 million years old. That is about five percent of the
universe's age of 14 billion years.

Scientists studying the UDF found this galaxy in Hubble's infrared
images. They expected it to be young and small, like other known
galaxies at similar distances. Instead, they found evidence the
galaxy is remarkably mature and much more massive, and its stars
appear to have been in place for a long time.

Hubble's optical-light UDF image is the deepest image ever taken,
yet this galaxy was not evident. This indicates much of the galaxy's
optical light has been absorbed by traveling billions of light-years
through intervening hydrogen gas. The galaxy was detected using
Hubble's Near Infrared Camera and Multi-Object Spectrometer. It was
also detected by an infrared camera on the Very Large Telescope (VLT)
at the European Southern Observatory. At those longer infrared
wavelengths, it is very faint and red.

The big surprise is how much brighter the galaxy is in even
longer- wavelength infrared images from the Spitzer Space Telescope.
Spitzer is sensitive to the light from older, redder stars, which
should make up most of the mass in a galaxy. The infrared brightness
of the galaxy suggests it is massive. "This would be quite a big galaxy

even today," said Mark Dickinson of the National Optical Astronomy
Observatory, Tucson, Ariz. "At a time when the universe was
only 800 million years old, it's positively gigantic," he added.

Spitzer observations were also independently reported by Laurence
Eyles from the University of Exeter in the United Kingdom and Haojing
Yan of the Spitzer Science Center, Pasadena, Calif. They also revealed
evidence for mature stars in more ordinary, less massive galaxies at
similar distances, when the universe was less than one billion years
old.

The new observations reported by Mobasher extend this notion of
surprisingly mature "baby galaxies" to an object which is perhaps
10 times more massive, and which seemed to form its stars even earlier
in the history of the universe.

Mobasher's team estimated the distance to this galaxy by combining
information provided by the Hubble, Spitzer, and VLT observations.
The relative brightness of the galaxy at different wavelengths is
influenced by the expanding universe and allows astronomers to estimate
its distance. They can also get an idea of the make-up of the galaxy
in terms of the mass and age of its stars.
It will take the next generation of telescopes, such as the infrared
James Webb Space Telescope, to confirm the galaxy's distance.

While astronomers generally believe most galaxies were built piecewise
by mergers of smaller galaxies, the discovery of this object suggests
at least a few galaxies formed quickly long ago. For such a large
galaxy, this would have been a tremendously explosive event of star
birth.

Mobasher's results will appear in the Astrophysical Journal on
Dec. 20.

For electronic images from the research and information on the Web,
visit:
http://hubblesite.org/news/2005/28
For information about NASA and agency programs on the Web, visit:
http://www.nasa.gov/home

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