From: baalke@zagami.jpl.nasa.gov   
      
   Royal Astronomical Society Press Notice   
   London, U.K.   
      
   Issued by Peter Bond, RAS Press Officer   
   PeterRBond@aol.com   
   tel: +44 (0)1483-268672fax: +44 (0)1483-274047   
      
   CONTACTS   
      
   Professor Michael Rowan-Robinson   
   Astrophysics Group   
   Blackett Laboratory   
   Imperial College   
   Prince Consort Road   
   London SW7 2BW   
   Tel: +44 (0)207-594-7530 or (0)208-444-0170 until 21 August.   
   Mobile +44 (0)781-793-9950   
   E-mail: mrr@ic.ac.uk   
      
   Dr. Sebastian Oliver   
   Astronomy Centre   
   University of Sussex   
   Falmer   
   Brighton BN1 9QJ   
   Tel: +44 (0)1273-67-8852 or (0)1273-697829   
   Mobile: +44 (0)797-101-9161   
   E-mail: S.Oliver@sussex.ac.uk   
      
   University of Sussex press contacts:   
   Jacqui Bealing or Peter Simmons   
   Tel: 01273 678888   
   Fax: 01273 877456   
   E-mail: J.A.Bealing@sussex.ac.uk or P.J.Simmons@sussex.ac.uk   
      
   Date: 18 August 2003   
      
   PN03-33   
      
   UK ASTRONOMERS LOOK FORWARD TO LOOKING BACK   
      
   When NASA launches its Space Infrared Telescope Facility (SIRTF) -- the   
   agency's   
   fourth 'Great Observatory' -- later this week, astronomers around the world   
   will   
   be looking forward to using one of the most powerful time machines ever built.   
      
   Among those anticipating the opportunity to look back billions of years to an   
   era when the universe was in its youth are Professor Michael Rowan-Robinson   
   (Imperial College London) and Dr. Sebastian Oliver (University of Sussex), who   
   will be participating in the international SIRTF Wide-area InfraRed   
   Extragalactic (SWIRE) survey.   
      
   Taking advantage of SIRTF's ability to detect infrared radiation (heat) from   
   the   
   coolest objects in the universe, the SWIRE team will study galaxies located up   
   to 10 billion light years away where infant stars are beginning to emerge from   
   the dust clouds in which they were born.   
      
   Over a period of nine months, the SWIRE survey will observe seven areas of the   
   sky covering a total of 65 square degrees -- equivalent to the area taken up by   
   360 full moons. These areas have been carefully selected because they are   
   exceptionally transparent due to an absence of Galactic dust.   
      
   Using all 7 SIRTF wavebands (3.6, 4.5, 5.8, 8, 24, 70 and 160 microns), SWIRE   
   is   
   expected to detect more than 1 million infrared galaxies, many of them dusty,   
   star-forming galaxies that existed when the universe was only about three   
   billion years old.   
      
   "We shall be studying star-forming galaxies and quasars at high redshifts,   
   looking far deeper in the infrared than any previous survey," said Professor   
   Rowan-Robinson, Deputy Principal Investigator for the SWIRE programme.   
      
   "By looking back through almost 90% of the universe's history, we shall be able   
   to look back to a period when star formation was much more frequent than it is   
   today," he added. "This will enable us to trace the evolution of star formation   
   from very early times."   
      
   "This is the most exciting and the most important project I have ever been   
   involved with," said Sebastian Oliver, a SWIRE Co-Investigator. "Our infrared   
   survey will be combined with studies by ground-based telescopes (such as the UK   
   Infrared Telescope in Hawaii) and by orbiting observatories, such as the Hubble   
   Space Telescope, Chandra and XMM-Newton, that study the universe at other   
   wavelengths."   
      
   "The SWIRE survey will provide our first glimpse of many distant galaxies," he   
   added.   
      
   "Long ago, galaxies were much closer together, and we think that colliding   
   galaxies triggered periods of rapid star birth and quasar activity. We expect   
   to   
   see thousands of colliding galaxies in the ancient universe, and this will help   
   us to explain how galaxies grew and evolved."   
      
   NOTES FOR EDITORS   
      
   The SWIRE team is led by Dr. Carol Lonsdale at the Infrared Processing and   
   Analysis Center, California Institute of Technology.   
      
   SWIRE is the largest of the 6 major 'Legacy' observational programmes being   
   undertaken with SIRTF. These projects utilise a total of 3160 hours of SIRTF   
   observing time, primarily in the first year of the mission, and integrate   
   substantial ancillary data from ground-based observatories and other   
   space-borne   
   telescopes.   
      
   A Boeing Delta 2 rocket carrying SIRTF is currently scheduled for launch from   
   Cape Canaveral, Florida on August 23 at 05:37 GMT (06:37 BST).   
      
   SIRTF is the fourth and last of NASA's Great Observatories. Two of these, the   
   Hubble Space Telescope and the Chandra X-ray Observatory are currently   
   operational. The Compton Gamma Ray Observatory re-entered Earth's atmosphere on   
   4 June 2000.   
      
   Originally intended as a $2 billion observatory that would be launched by the   
   space shuttle, SIRTF has suffered prolonged delays as the result of downsizing   
   and redesign of the spacecraft.   
      
   The new observatory is still the largest, most sensitive infrared space   
   observatory ever built, although its mirror is 'only' 85 cm (33 inches) in   
   diameter, much smaller than the Hubble Space Telescope or modern ground-based   
   telescopes. It carries three cryogenically cooled instruments incorporating   
   state-of-the-art infrared detectors.   
      
   The telescope will be cooled to a temperature of -268 C (only 5.2 C above   
   absolute zero) by a tank containing 360 litres of liquid helium.   
      
   SIRTF is expected to operate for at least two-and-a-half years, with a goal of   
   five years. Some of its detectors will be able to operate even after the supply   
   of helium runs out.   
      
   Following launch, the spacecraft will drift slowly away from our planet into   
   deep space, receding from us at a rate of about 9 million miles per year. By   
   following this remote, Earth-trailing orbit, heat 'pollution' from the Earth   
   and   
   Moon will be reduced. Observations will also be made easier because the Earth   
   will not be blocking the view and there will be no periods in the planet's   
   shadow.   
      
   The mission is a cornerstone of NASA's Origins Programme, which seeks to answer   
   the questions "Where did we come from? Are we alone?"   
      
   Observing at infrared wavelengths between 3 and 180 microns, SIRTF will be able   
   to study the coolest objects in the universe and probe the dense dust clouds   
   that block visible light. The four main areas of study will be:   
      
   * Brown dwarfs (small, failed stars) and giant gas planets around other stars.   
   * The discovery and study of debris disks around nearby stars.   
   * Ultraluminous infrared galaxies and quasars   
   * The early universe -- when and how the first stars and galaxies formed.   
      
   UK astronomers are currently helping to develop a much larger infrared   
   telescope, known as Herschel, which will be launched by the European Space   
   Agency in 2007.   
      
   Infrared radiation was discovered in 1800 by the German-born British   
   astronomer,   
   William Herschel.   
      
   FURTHER INFORMATION   
      
   * SIRTF home page   
      http://sirtf.caltech.edu/   
   * Imperial College London   
      http://astro.ic.ac.uk/   
      
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