Stars burst into life in the early Universe (Forwarded)

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Anita Heward
Tel: +44 (0)1483 420904

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Tel: +44 (0)2890 975262 / 975263 / 975264

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CONTACTS

Dr Scott Chapman
Institute of Astronomy
University of Cambridge
Madingley Road
Cambridge CB3 0HA
E-mail: schapman at ast.cam.ac.uk
Tel: +44 (0)1223 330803

Caitlin Casey
Institute of Astronomy
University of Cambridge
Madingley Road
Cambridge CB3 0HA
E-mail: ccasey at ast.cam.ac.uk

Professor Frank Bertoldi
University of Bonn
Bonn
Germany
E-mail: bertoldi at astro.uni-bonn.de

Dr Tom Muxlow
Jodrell Bank Observatory
University of Manchester
Macclesfield SK11 9DL
UK
E-mail: twbm at jb.man.ac.uk

Professor Ian Smail
Institute for Computational Cosmology
Durham University
South Road
Durham DH1 3LE
UK
E-mail: ian.smail at durham.ac.uk

Professor Andrew Blain
California Institute of Technology
Pasadena
CA 91125
E-mail: awb at astro.caltech.edu

Professor Rob Ivison
Institute for Astronomy
University of Edinburgh
Royal Observatory
Blackford Hill
Edinburgh EH9 3HJ
UK
E-mail: rji at roe.ac.uk

EMBARGOED UNTIL 0001 BST, 1 April 2008

Ref.: PN 08/12 (NAM 03)

Stars burst into life in the early Universe

New measurements from some of the most distant galaxies bolster the evidence
that the strongest burst of star formation in the history of the Universe
occurred about two billion years after the Big Bang. An international team
of astronomers from the UK, France, Germany and the USA have found evidence
for a dramatic surge in star birth in a newly discovered population of
massive galaxies in the early Universe.

In his talk at the RAS National Astronomy Meeting in Belfast on Tuesday 1
April, team member Dr Scott Chapman from the Institute of Astronomy in
Cambridge will present observations of five of these galaxies that are
forming stars at a tremendous rate and have large reservoirs of gas that
will power the star formation for hundreds of millions of years. Dr
Chapman's work is supported by a parallel study made by PhD student Caitlin
Casey, who finds that the star formation in the new galaxies is distributed
over a vast area.

The galaxies are so distant that the light we detect from them has been
travelling for more than 10 billion years. This means that we see them as
they were about a three billion years after the Big Bang. The recent
discovery of a new type of extremely luminous galaxy in this epoch -- one
that is very faint in visible light, but much brighter at longer, radio
wavelengths -- is the key to the new results.

A related type of galaxy was first found in 1997 (but not well understood
until 2003) using a new and much more sensitive camera that detects
radiation emitted at submillimetre wavelengths (longer than the wavelengths
of visible light that we see with but somewhat shorter than radio waves).
The camera, called 'SCUBA' was attached to the James Clerk Maxwell Telescope
(JCMT), on Mauna Kea in Hawaii.

In 2004 the Cambridge-led team of astronomers proposed that these distant
"submillimetre-galaxies" might only represent half of the picture of rapid
star formation in the early Universe, as SCUBA is biased towards colder
objects. They suggested that a population of similar galaxies with slightly
hotter temperatures could exist but have gone largely unnoticed.

The team of scientists searched for the missing galaxies using observatories
around the world: the MERLIN array in the UK, the Very Large Array (VLA) in
the US (both radio observatories), the Keck optical telescope on Hawaii and
the Plateau de Bure submillimetre observatory in France. The instruments
found and pinpointed the galaxies, measured their distances and then
confirmed their star forming nature through the detection of the vastly
extended gas and dust.

The new galaxies have prodigious rates of star formation, far higher than
anything seen in the present-day Universe. They probably developed after the
first stars and galaxies had already formed in what would have been a
perfectly smooth Universe. None the less, studying these new objects gives
astronomers an insight into the earliest epochs of star formation after the
Big Bang.

With the new discovery, the Cambridge astronomers have provided a much more
accurate census of some of the most extreme galaxies in the Universe at the
peak of their activity. Future observations will investigate the details of
the galaxies' power source and try to establish how they will develop once
their intense bursts of activity come to an end.

IMAGES AND FURTHER INFORMATION

Images and movie
http://www.ast.cam.ac.uk/~ccasey/sfrg.html

Plateau de Bure Interferometer
http://www.iram.fr/IRAMFR/index.htm

MERLIN
http://www.merlin.ac.uk/

NOTES FOR EDITORS

The Plateau de Bure Interferometer is managed by IRAM. IRAM is supported by
the Max-Planck-Society, INSU/CNRS (France), and IGN (Spain).

MERLIN is operated by the University of Manchester as a National Facility of
the Science and Technology Facilities Council (STFC).

The RAS National Astronomy Meeting (NAM 2008) is hosted by Queen's
University Belfast. It is principally sponsored by the RAS and the Science
and Technology Facilities Council (STFC). NAM 2008 is being held together
with the UK Solar Physics (UKSP) and Magnetosphere, Ionosphere and
Solar-Terrestrial (MIST) spring meetings.