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.