From: LARRY KLAES (ljk4_at_msn.com)
Date: Sat Feb 14 2004 - 07:27:04 PST
>From: Laura Kraft <lkraft_at_keck.hawaii.edu>
>To: "'news_at_keckobservatory.org'" <news_at_keckobservatory.org>
>Subject: HUBBLE AND KECK TEAM UP TO FIND FARTHEST KNOWN GALAXY IN THE
>UNIVERSE
>Date: Fri, 13 Feb 2004 17:56:11 -1000
>
>EMBARGOED UNTIL 7:00 a.m. Hawaii Time SUNDAY February 15, 2004
>(9:00 Pacific/12:00 pm Eastern/18:00 Europe)
>
>On the Web: http://www2.keck.hawaii.edu/news/draftz_7.html
>
>Media Contact:
>Laura K. Kraft
>CARA/W. M. Keck Observatory, Kamuela, HI
>(808) 885-7887
>lkraft_at_keck.hawaii.edu
>
>Robert Tindol
>Caltech, Pasadena, CA
>(626) 395-3631
>tindol_at_caltech.edu
>
>Ray Villard
>Space Telescope Science Institute, Baltimore, MD;
>(410) 338-4514
>villard_at_stsci.edu
>
>Lars Lindberg Christensen
>Hubble European Space Agency Information Centre, Garching, Germany
>+49-89-320-06-306
>lars_at_eso.org
>
>
>HUBBLE AND KECK TEAM UP TO FIND FARTHEST KNOWN GALAXY IN THE UNIVERSE
>
>KAMUELA, Hawaii (February 15, 2004) A team of astronomers may have
>discovered the most distant galaxy in the universe. Located an estimated 13
>billion light-years away, the object is being viewed at a time only 750
>million years after the big bang, when the universe was barely 5 percent of
>its current age.
>
>The primeval galaxy was identified by combining the power of NASA's Hubble
>Space Telescope and CARA's W. M. Keck Telescopes on Mauna Kea in Hawaii.
>These great observatories got a boost from the added magnification of a
>natural "cosmic gravitational lens" in space that further amplifies the
>brightness of the distant object.
>
>"We are looking at the first evidence of our ancestors on the evolutionary
>tree of the entire universe," said Dr. Frederic Chaffee, director of the W.
>M. Keck Observatory, home to the twin 10-meter Keck telescopes that
>confirmed the discovery. "Telescopes are virtual time machines, allowing
>our
>astronomers to look back to the early history of the cosmos, and these
>marvelous observations are of the earliest time yet."
>
>The newly discovered galaxy is likely to be a young galaxy shining during
>the end of the so-called "Dark Ages" -- the period in cosmic history which
>ended with the first galaxies and quasars transforming opaque, molecular
>hydrogen into the transparent, ionized universe we see today.
>
>The new galaxy was detected in a long exposure of the nearby cluster of
>galaxies Abell 2218, taken with the Advanced Camera for Surveys on board
>the
>Hubble Space Telescope. This cluster is so massive that the light of
>distant
>objects passing through the cluster actually bends and is amplified, much
>as
>a magnifying glass bends and magnifies objects seen through it. Such
>natural
>gravitational "telescopes" allow astronomers to see extremely distant and
>faint objects that could otherwise not be seen. The extremely faint galaxy
>is so far away its visible light has been stretched into infrared
>wavelengths, making the observations particularly difficult.
>
>"As we were searching for distant galaxies magnified by Abell 2218, we
>detected a pair of strikingly similar images whose arrangement and color
>indicate a very distant object," said California Institute of Technology
>(Caltech) astronomer Jean-Paul Kneib, who is lead author reporting the
>discovery in a forthcoming article in the Astrophysical Journal.
>
>Analysis of a sequence of Hubble images indicate the object lies in between
>a redshift of 6.6 and 7.1, making it the most distant source currently
>known. However, long exposures in the optical and infrared taken with
>spectrographs on the 10-meter Keck telescopes suggests that the object has
>a
>redshift towards the upper end of this range, around redshift 7.
>
>Redshift is a measure of how much the wavelengths of light are shifted to
>longer wavelengths. The greater the shift in wavelength toward the redder
>regions of the spectrum, the more distant the object is.
>
>"The galaxy we have discovered is extremely faint, and verifying its
>distance has been an extraordinarily challenging adventure," said Dr.
>Kneib.
>"Without the magnification of 25 afforded by the foreground cluster, this
>early object could simply not have been identified or studied in any detail
>at all with the present telescopes available. Even with aid of the cosmic
>lens, the discovery has only been possible by pushing our current
>observatories to the limits of their capabilities!"
>
>Using the combination of the high resolution of Hubble and the large
>magnification of the cosmic lens, the astronomers estimate that this
>object,
>although very small -- only 2,000 light-years across -- is forming stars
>extremely actively. However, two intriguing properties of the new source
>are
>the apparent lack of the typically bright hydrogen emission line and its
>intense ultraviolet light which is much stronger than that seen in
>star-forming galaxies closer by.
>
>"The properties of this distant source are very exciting because, if
>verified by further study, they could represent the hallmark of a truly
>young stellar system, that ended the Dark Ages," added Dr. Richard Ellis,
>Steele Professor of Astronomy at Caltech, and a co-author in the article.
>
>The team is encouraged by the success of their technique and plans to
>continue the search for more examples by looking through other cosmic
>lenses
>in the sky.
>
>"Estimating the abundance and characteristic properties of sources at early
>times is particularly important in understanding how the universe reionized
>itself, thus ending the Dark Ages," said Mike Santos, a former Caltech
>graduate student, now a postdoctoral researcher at the Institute of
>Astronomy, Cambridge, UK. "The cosmic lens has given us a first glimpse
>into
>this important epoch. We are now eager to learn more by finding further
>examples, although it will no doubt be challenging."
>
>The Caltech team reporting on the discovery consists of Drs. Jean-Paul
>Kneib, Richard S. Ellis, Michael R. Santos and Johan Richard. Drs. Kneib
>and
>Richard also serve the Observatoire Midi-Pyrenees of Toulouse, France. Dr.
>Santos also represents the Institute of Astronomy, Cambridge, UK.
>
>The W.M. Keck Observatory is operated by the California Association for
>Research in Astronomy, a scientific partnership of the California Institute
>of Technology, the University of California, and the National Aeronautics
>and Space Administration.
>
># # #
>
>
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