Embargoed until Monday 19 July 2004 05.00 GMT
Spitzer Space Telescope pinpoints elusive
but violent starbursts
A major breakthrough in pinpointing some of the most primordial
and violently star forming galaxies in the Universe has been made by a joint
collaboration of UK and US astronomers using the Spitzer Space Telescope to
resolve primordial galaxies initially detected by the James Clerk Maxwell
telescope [JCMT]. UK astronomers from the University of Kent, The Royal Observatory
Edinburgh and the University of Oxford teamed up with American cosmologists
to finally identify these elusive galaxies. The work will be published in
the Astrophysical Journal Supplement Spitzer Special Issue in September 2004.
Back in 1995, the UK's SCUBA camera (Sub-millimetre Common User Bolometer
Array) on the James Clerk Maxwell Telescope in Hawaii, which detects
light with wavelengths just under a millimetre, began finding fuzzy traces
of very distant, primordial galaxies. Some of these are either too distant
or too dusty to be seen even by the Hubble Space Telescope. But SCUBA's
images on their own, and those of other similar cameras, are not fine enough:
within the fuzzy SCUBA detections are sometimes many galaxies. So astronomers
have spent enormous effort following up these SCUBA galaxies on other telescopes,
particularly radio telescopes, to answer the question: which one is the
primordial galaxy, and which ones are in the foreground? But even with
the most sensitive radio telescope images ever made, only around half the
SCUBA galaxies can be pinpointed unambiguously. Even worse, the radio telescopes
miss all of the most distant and most primordial of SCUBA's galaxies.
UK and US astronomers teamed up to combine Spitzer's sharp
images with SCUBA's ability to find primordial galaxies. The team
were stunned to find all the SCUBA galaxies in Spitzer’s field of
view detected in only ten minutes with Spitzer. These breakthrough
observations, described as a ‘watershed’ by the team, finally give astronomers
a way of unambiguously pinpointing even the most distant of SCUBA's galaxies.
This could only be done by combining SCUBA with the Spitzer Space Telescope:
SCUBA shows there is a primordial, violent starburst somewhere in the
vicinity, which is then pinpointed by Spitzer.
At the same time, Spitzer solved another mystery about SCUBA galaxies.
When Galileo first trained a telescope at the Milky Way, he was astonished
to find the fuzzy light resolved into many individual stars. This is,
in essence, what the team of astronomers have done with the diffuse extragalactic
background light seen from all directions at a wavelength of about half
a millimetre. By comparing the distinct Spitzer galaxies with the SCUBA
data, the team discovered that they had identified the sources of this cosmic
background for the first time. This background is caused by an important
population of galaxies: most of the stars in the early Universe are created
in these galaxies, and star formation is where everything comes from - including
the material that makes planets like our own. Finding where this star formation
happens tells us, in a sense, where we came from. Identifying most of
these galaxies is a second coup for the joint UK/US team.
Dr. Stephen Serjeant (University of Kent, UK) said, ‘Our
Spitzer Space Telescope images picked our galaxies out astonishingly
quickly, in only ten minutes, when the community has been pouring effort
into detecting them. This really is pioneering work and a great triumph
for the Spitzer Space Telescope and the UK’s SCUBA camera. To cap it
all, at the same time we’ve found the galaxies that dominate the star
formation in the early Universe. The Earth and everything on it is made
from the dust created in stars like those – people, trees, beef burgers,
the lot.’
Dr. Rob Ivison (Royal Observatory Edinburgh, UK) said, ‘In
10 minutes, the Spitzer Space Telescope has managed to pinpoint the
galaxies we have been chasing for 7 years. We can finally begin to
sort the babies and teenagers of the galaxy world from the adults and
senior citizens.’
Dr. Hervé Dole (University of Arizona USA and IAS, Orsay,
France) said, ‘These Spitzer observations were designed as the first
joint survey using the MIPS and IRAC instruments on Spitzer, to assess
the instrument sensitivities. As a matter of fact, it's a great technological,
operational and scientific success, overwhelming our wildest expectations.
This demonstrates the amazing capabilities of Spitzer for studying galaxy
evolution at high redshifts; no doubt that deeper and larger ongoing
surveys will give even more exciting results!’
Dr. Steve Willner (Harvard-Smithsonian Center for Astrophysics,
USA) said, ‘We expected to detect one or a few of these galaxies, but
I was stunned that we detected all of the ones we looked at. The new
data finally tell us what these galaxies are all about. We've known
all along that they had to be far away and rapidly turning all their
gas into stars, but now we know their true distances and ages.’
Images available at http://astro.kent.ac.uk/~sbgs/press_release
(username: scuba password: scuba)
Above: Each panel shows the fuzzy
thermal light images detected by the UK’s SCUBA camera (left, brown),
and the corresponding view from NASA’s Spitzer Space Telescope (right,
colour). The galaxies emitting the heat detected by SCUBA are shown
with an arrow. Astronomers believe the heat is generated in violent
starbursts. The colour Spitzer pictures are made from Spitzer’s infrared
images at wavelengths of 3.6-8 microns, and are roughly what the human
eye would see if it were sensitive to the same light as Spitzer.
Below: The whole of Spitzer’s images, combined to make an
image roughly corresponding to what the human eye would see if it were sensitive
to the same light as Spitzer. Image below available as
JPEG (51 kb), GIF (151 kb) or TIFF (451 kb) (credit:
University of Kent / University of Arizona / IAS Orsay France)
Contact details
Dr Stephen Serjeant
Centre for Astrophysics and Planetary Science
School of Physical Sciences
University of Kent
Canterbury, Kent, CT2 7NR, UK
Tel: +44 (0)1227-827346 (Office); +44 (0)7946-605913 (Mobile);
+44 (0)1227 767570 (Home)
Fax: +44 (0)1227-827558
email: s. serjeant (at) kent .ac. uk
Dr Rob Ivison
Astronomy Technology Centre
Royal Observatory Edinburgh
email: rji@roe.ac.uk
Tel: +44 (0)131 668 8361 (direct)
Home tel: +44 (0)131 477 2573
Fax: +44 (0)131 668 8407
Dr Hervé Dole
Institut d'Astrophysique Spatiale
bat 121, Université Paris Sud
F-91405 Orsay Cedex, France
Phone: +33 1 6985 8572
Fax: +33 1 6985 8675
Email: Herve.Dole (at) ias.u-psud.fr
Dr Steve Willner
Harvard-Smithsonian Center for Astrophysics
60 Garden Street
Cambridge, MA 02138
USA
Home phone: +1 781-455-8687
Office phone: +1 617-495-7123
email: willner (at) cfa.harvard.edu
Dr Eiichi Egami
Steward Observatory, Univ. of Arizona
933 North Cherry Avenue
Tucson, AZ 85721-0065, USA
email: eegami (at) as.arizona.edu
Tel: +1 520-621-3161
Dr Giovanni Fazio
Harvard-Smithsonian Center for Astrophysics
60 Garden Street
Cambridge, MA 02138
USA
Home phone: +1 617-969-8055
Office phone: +1 617-495-7458
Cell phone: +1 617-799-6768
Fax: 617-495-7490
email: gfazio (at) cfa.harvard.edu
Dr Douglas Pierce Price - for queries about the James Clerk Maxwell Telescope
Joint Astronomy Centre, Hawaii
Email: outreach@jach.hawaii.edu (contact by email out of office
hours)
Tel: +1 808 969 6524
Fax: +1 808 961 6516
Dr. Dimitra Rigopoulou
UK Gemini Office
Department of Astrophysics
Oxford University
Keble Rd, Oxford, OX1 3RH, U.K.
email: d.rigopoulou1 (at) physics.ox.ac.uk
phone: +44 (0) 1865 273319 / 273335
fax: +44 (0) 1865 283132
University of Kent Press Office:
Communications and Development Office
University of Kent
Canterbury, Kent
email: mediaoffice (at) kent.ac.uk
Tel: +44 (0)1227 824343
Royal Observatory Edinburgh Press Officer:
Eleanor Gilchrist
email: efg (at) roe.ac.uk
Tel: +44 (0)131 668 8397
Center for Astrophysics press office:
David Aguilar and Christine Pulliam
Harvard-Smithsonian Center for Astrophysics
Science Education Department, MS-28
60 Garden Street, Cambridge MA 02138, USA
Phone: +1 617-495-7462/3
Fax: +1 617-496-7670
email: daguilar (at) cfa.harvard.edu or cpulliam (at) cfa.harvard.edu
Notes for editors
The teams span the UK and USA.
USA: University of Arizona; Space Science Institute, Boulder,
Colorado; California Institute of Technology; Harvard-Smithsonian Center
for Astrophysics.
UK: University of Kent; Royal Observatory Edinburgh; University
of Edinburgh; University of Oxford.
The observations will be published in the Astrophysical Journal
Supplement Spitzer Special Issue, in September 2004:
The James Clerk Maxwell Telescope (JCMT) is the world's largest
single-dish submillimetre-wave telescope. It collects faint submillimetre-wavelength
signals with its 15 metre diameter dish. It is situated near the summit
of Mauna Kea on the Big Island of Hawaii, at an altitude of approximately
4000 metres (14000 feet) above sea level. It is operated by the Joint
Astronomy Centre, on behalf of the UK Particle Physics and Astronomy
Research Council, the Canadian National Research Council, and the Netherlands
Organisation for Scientific Research. More about the James Clerk Maxwell
Telescope and SCUBA: http://outreach.jach.hawaii.edu/articles/aboutjcmt/
The UK Astronomy Technology centre is located at the Royal
Observatory, Edinburgh (ROE). It is a scientific site belonging to
the Particle Physics and Astronomy Research Council (PPARC). The mission
of the UK ATC is to support the mission and strategic aims of PPARC and
to help keep the UK at the forefront of world astronomy by providing a
UK focus for the design, production and promotion of state of the art
astronomical technology.
The Royal Observatory, Edinburgh comprises the UK Astronomy
Technology Centre (UK ATC) of the Particle Physics and Astronomy Research
Council (PPARC), the Institute for Astronomy (IfA) of the University of
Edinburgh and the ROE Visitor Centre.
The Particle Physics and Astronomy Research Council (PPARC)
is the UK's strategic science investment agency. It funds research, education
and public understanding in four broad areas of science - particle physics,
astronomy, cosmology and space science.
Spitzer was originally known as SIRTF (Space Infrared Telescope
Facility) and is the last of NASA’s four Great Observatories. It was
launched on August 25th, 2003. IRAC (Infrared Array Camera) and MIPS (Multiband
Imaging Photometer for Spitzer) are the two of Spitzer’s instruments involved
in these results. More information on Spitzer can be found at http://www.spitzer.caltech.edu
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