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. Herve 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
Images available at http://astro.kent.ac.uk/~sbgs/press_release
(Credit: University of Kent)
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@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 Herve Dole
Institut d’Astrophysique Spatiale
bat 121, Universite Paris Sud
F-91405 Orsay Cedex, France
Phone: +33 1 6985 8572
Fax: +33 1 6985 8675
Email: Herve.Dole@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@cfa.harvard.edu
Dr Eiichi Egami
Steward Observatory, Univ. of Arizona
933 North Cherry Avenue
Tucson, AZ 85721-0065, USA
email: eegami@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@cfa.harvard.edu
Dr Douglas Pierce Price – for queries about the James Clerk Maxwell
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@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@kent.ac.uk
Tel: +44 (0)1227 824343
Royal Observatory Edinburgh Press Officer:
Eleanor Gilchrist
email: efg@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@cfa.harvard.edu or cpulliam@cfa.harvard.edu
