Quasars, the most brilliant of cosmic fireworks, appear to shine forth
from humdrum galaxies in the early universe, not the giant or disrupted
ones astronomers expected. This is according to a team of Australian,
Canadian and UK astronomers who studied an assortment of quasars near
the edge of the observable universe using the Frederick C. Gillett
Gemini North Telescope on Hawaii’s Mauna Kea. Their findings were
presented today (May 25th) at the first Gemini Science Conference by Dr
David Schade of the Dominion Astrophysical Observatory, Victoria,
Canada.

The quasars’ pedestrian surroundings came as a shock. “It’s like
finding a Formula One racing car in a suburban garage,” said Dr Scott
Croom of the Anglo-Australian Observatory in Australia who led the
study. Put another way, “On our previous idea that brighter Quasars
should inhabit brighter host galaxies, these observations were a bit of
an insult to the superb
Gemini North telescope! These observations should really have been like
using a magnifying glass to find an elephant. Instead, these host
galaxies turned out to be more like little mice, despite their
brilliant roar!” said team-member Professor Tom Shanks from the
University of Durham (UK).

It is thought that quasars are located in the central cores of galaxies
where matter falling onto a supermassive black hole is turned into a
blinding torrent of radiation. Quasars flourished when the universe was
between a tenth and a third of its present age.

“This finding is particularly exciting because it means that we may
need to re-think our models of how quasars work. This isn’t the first
time quasars have done this to us, it seems that quasars like to keep
us guessing!” said Dr. Schade.

The research team attempted to obtain some of the first-ever detailed
infrared views of the host galaxies-nine in all-each about 10 billion
light-years away. “We’d hoped their sizes and shapes might give clues
as to what triggered quasar activity,” said Dr Croom. Instead, the
team found that all but one of the galaxies were too faint or small to
detect, even though the data’s sensitivity and resolution were
exceptionally high. The one convincing detection was remarkably
unremarkable, similar in brightness and size to our own Galaxy.

Many astronomers had anticipated that a quasar’s host galaxy would be
large, and might show signs of having collided with another
galaxy-violence that could spark a quasar into brilliance. The team’s
finding will undoubtedly add fuel to the debate regarding how galaxies
and black holes form and grow.

Astronomers have used other telescopes, on the ground and in space to
look for very distant quasar host galaxies but the results have been
inconclusive. “For this study, the Gemini telescope was able to produce
an image sharpness that is usually only possible by using the Hubble
Space Telescope,” said Professor Shanks. “But Gemini’s larger mirror
can collect ten times more light to study faint objects.” The image
detail was achieved with a technology called adaptive optics to remove
distortions to starlight caused by atmospheric turbulence. This
combination provided a powerful capability that produced some of the
deepest (faintest) and sharpest infrared images ever obtained of
objects in the early universe.

One of the difficulties inherent in this study was to find quasars that
were close to the relatively bright guide stars necessary to use
adaptive optics technology. To find the necessary sample size, the
team drew on a database of more than 20,000 quasars gathered with the
Anglo-Australian Telescope between 1997 and 2002. This work represents
the largest quasar survey ever attempted and, “*the only one in which
we could hope to find a decent sample of quasars to meet our
requirements,” said Dr. Croom.

This work was published in The Astrophysical Journal 606 (2004) 126-138
And is also available at: Astro-ph:
http://xxx.lanl.gov/abs/astro-ph/0401442

Notes for Editors

An artist’s impression and scientific images are available at:
http://www.gemini.edu/project/announcements/press/2004-11.html#science

UK involvement

UK astronomers from the Universities of Durham, Oxford and Liverpool
John Moores were involved in producing this research (see contact
details for names). The UK’s Particle Physics and Astronomy Research
Council is a funder of both the Gemini Observatory and the
Anglo-Australian Observatory.

Quasars

Quasars are a class of objects that are located at great distances from
us and thus represent the universe at a relatively young age. Quasars
are intrinsically extremely bright (considering their distances from
us) and this extreme brightness has been a challenge to explain. It is
thought that quasars shine due to intense activity in cores of young
galaxies where supermassive black holes fuel these intensely luminous
beacons. Today, we see what astronomers believe are the remnant black
holes of this youthful excess at the cores of normal stable galaxies
like our Milky Way.

This work at Gemini shows that the galaxies responsible for a quasar’s
luminosity were not exceptional or even undergoing extraordinary events
(like collisions) to produce the excessive radiation. To explain this,
it is speculated that in the distant history of our universe, black
holes grew by swallowing large quantities of cold, dense gas from which
stars form. In the early universe, this gas was much more common that
it is now, having mostly been turned into stars by the present day.

Adaptive Optics

For an explanation of how adaptive optics works, see:
http://www.gemini.edu/project/announcements/press/pr2003-2_background.html

Gemini Observatory

The Gemini Observatory is an international collaboration that has built
two identical 8-meter telescopes. The Frederick C. Gillett Gemini
Telescope is located on Mauna Kea, Hawai`i (Gemini North) and the
Gemini South telescope is located on Cerro Pachon in central Chile
(Gemini South), and hence provide full coverage of both hemispheres of
the sky. Both telescopes incorporate new technologies that allow large,
relatively thin mirrors under active control to collect and focus both
optical and infrared radiation from space.

The Gemini Observatory provides the astronomical communities in each
partner country with state-of-the-art astronomical facilities that
allocate observing time in proportion to each country’s contribution.
In addition to financial support, each country also contributes
significant scientific and technical resources. The national research
agencies that form the Gemini partnership include: the US National
Science Foundation (NSF), the UK Particle Physics and Astronomy
Research Council (PPARC), the Canadian National Research Council (NRC),
the Chilean Comision Nacional de Investigacion Cientifica y
Tecnologica (CONICYT), the Australian Research Council (ARC), the
Argentinean Consejo Nacional de Investigaciones Cientificas y
Tecnicas (CONICET) and the Brazilian Conselho Nacional de
Desenvolvimento Cientifico e Tecnologico (CNPq). The Observatory is
managed by the Association of Universities for Research in Astronomy,
Inc. (AURA) under a cooperative agreement with the NSF. The NSF also
serves as the executive agency for the international partnership.

Media Contacts:

Peter Michaud (US Gemini)
Gemini Observatory, Hilo, HI
+1 808 974-2510 (Desk)
+1 808 937-0845 (Mobile)
pmichaud@gemini.edu

Helen Sim (Australia)
Anglo-Australian Observatory
+61-2-9372-4251 (Desk)
+61-419-635-905 (Mobile)
Helen.Sim@csiro.au

Julia Maddock (UK)
PPARC
+44 (0) 1793-442094 (Desk)
+44 (0) 7901-514975 (Mobile)
julia.maddock@pparc.ac.uk

Science Contacts:

UK
Professor Tom Shanks, University of Durham, Durham, UK
Tel: +44-191-3742-171
Tom.Shanks@durham.ac.uk

Dr Lance Miller, University of Oxford, Oxford, UK
Tel: +44-1865-273342
L.Miller@physics.ox.ac.uk

Dr Robert J. Smith, Liverpool John Moores University, Liverpool, UK
Tel: +44-151-2312903
rjs@astro.livjm.ac.uk

AUSTRALIA
Dr Scott Croom, Anglo-Australian Observatory, Sydney, Australia
Tel: +61-2- 9372 4846
scroom@aaoepp.aao.GOV.AU

Professor Brian Boyle, Director, CSIRO Australia Telescope National
Facility, Sydney, Australia
Tel: +61-2-9372-4301
Brian.Boyle@csiro.au

CANADA
Dr David Schade, Dominion Astrophysical Observatory, Victoria, Canada
+1-250-363-6904 (Office)
+1-250-216-9970 (at Gemini Science Meeting 5/19-23/04)
David.Schade@nrc.ca

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 areas of science – particle physics,
astronomy, cosmology and space science.

PPARC is government funded and provides research grants and
studentships to scientists in British universities, gives researchers
access to world-class facilities and funds the UK membership of
international bodies such as the European Laboratory for Particle
Physics (CERN), and the European Space Agency. It also contributes
money for the UK telescopes overseas on La Palma, Hawaii, Australia and
in Chile, the UK Astronomy Technology Centre at the Royal Observatory,
Edinburgh and the MERLIN/VLBI National Facility, which includes the
Lovell Telescope at Jodrell Bank observatory.

PPARC’s Public Understanding of Science and Technology Awards Scheme
funds both small local projects and national initiatives aimed at
improving public understanding of its areas of science.