UK astronomers using the 15-m James Clerk Maxwell Telescope in Hawaii have
discovered enormous quantities of cosmic dust in the most distant quasar yet
observed. The quasar, called SDSS J1148+5251 is at a redshift (z) of 6.43,
and is found in the direction of the constellation of Ursa Major. It is some
13 billion light years away, and we are seeing it when the universe was very
young – only 900 million years after the Big Bang. Cosmic dust is made up
from elements, such as carbon and silicon, that are only produced deep
within stars, and released into space in large stellar explosions. So much
dust has been found – equivalent to 100 million times the mass of the Sun –
it means that many stars must have already formed and exploded during those
first 900 million years since the Big Bang – just one fifteenth the total
age of the universe and a short period of time astronomically speaking. The
observations are being reported at the UK/Ireland National Astronomy Meeting
in Dublin by Professor Ian Robson of the UK Astronomy Technology Centre,
Edinburgh.

The observations were made with the SCUBA camera on the James Clerk Maxwell
Telescope (JCMT) in Hawaii by a team of British astronomers in January 2003.
Professor Robson, who made the observations, said “For this work, SCUBA is
the most sensitive instrument in the world and the JCMT the best telescope
in the world. Fortunately the weather during the run was in our favour and
so this result was a fantastic achievement with a really surprising outcome,
a very exciting night indeed”.

Dr Kate Isaak of the Cavendish Laboratory Astrophysics Group at the
University of Cambridge, and a member of the team, said “The very fact that
we see such large quantities of dust at such early times in the lifetime of
the universe is amazing. By pushing to higher redshifts, we will be able to
gauge more accurately when the dust formed. It has to be sometime after the
Big Bang, but the radiation that we see today from these objects was emitted
not very long after the Big Bang.”

The observations were made at wavelengths of 0.85 and 0.45 mm, in the
submillimetre region of the spectrum. These are the precise wavelengths at
which cold dust in space shines brightest and SCUBA has searched for dust in
a wide variety of cosmic objects: its successes range from the detection of
spectacular dust rings around nearby stars, heralding planetary formation,
to the dust now seen in the most distant quasar in the universe.

Dr Robert Priddey from Imperial College, London, commenting on the
importance of the detections at both wavelengths said, “The detection at two
wavelengths may allow us to determine the temperature of the dust. I found
that the dust in other quasars that I have studied was colder than -200
degrees C.”

Dr Richard McMahon from the Institute of Astronomy at the University of
Cambridge said, “This quasar appears to be forming stars at a rate of
500-1000 solar masses per year, which is more than a 100 times faster than
the Milky Way.”

Everything now being learned, even the fact that this quasar exists so very
early in the history of the universe, means that galaxies and stars formed
much faster than previously thought at these very early times.

CONTACTS

Professor Ian Robson, UK Astronomy Technology Centre
Phone: (+44) (0)131-668-8438 (office), (+44) (0)7919 398610 (mobile)
email eir@roe.ac.uk

Dr Richard McMahon, Institute of Astronomy, University of Cambridge
Phone: (+44) (0)1223-337519 (office); (+44) (0)7885-409019(mobile)
email rgm@ast.cam.ac.uk

Dr Kate Isaac, Cavendish Laboratory, University of Cambridge
Phone: (+44) (0)1223 339242 (office), (+44) (0)7814-028-579 (mobile)
email isaak@mrao.cam.ac.uk

Dr Robert Priddey, Blackett Laboratory, Imperial College London
Phone: (+44) (0)20 7594 7543
email r.priddey@imperial.ac.uk

NOTE

The SCUBA camera was built at the Royal Observatory Edinburgh and has been
used on the JCMT since 1997. It has been responsible for many recent
important discoveries and is recognised as being one of the most successful
instruments ever in astronomy, a tribute to the builders and to the JCMT
agencies that provided the funding. The JCMT is operated by the Particle
Physics and Astronomy Research Council (PPARC) of the UK, the National
Research Council (NRC) of Canada and the National Organisation for
Scientific Research (NWO).