Sunday, December 11, 2011

Revolutionary new camera reveals the dark side of the Universe

A composite image of the Whirlpool Galaxy (also known as M51). The green image is from the Hubble Space Telescope and shows the optical wavelength. The submillimetre light detected by SCUBA-2 is shown in red (850 microns) and blue (450 microns). The Whirlpool Galaxy lies at an estimated distance of 31 million light years from Earth in the constellation Canes Venatici. Credit: JAC / UBC / Nasa

A new camera that will revolutionise the field of submillimetre astronomy has been unveiled on the James Clerk Maxwell Telescope (JCMT) (link opens in a new window) in Hawaii SCUBA-2 is far more sensitive and powerful than previous instruments
and can map areas of the sky hundreds of times faster.

SCUBA-2 will provide unprecedented information on the early life of stars - normally obscured by the remains of the very dust and gas cloud that collapsed under its own gravity to form the star.

"When you look up at the stars, you only see the light they are emitting in the visible part of the spectrum. Many galaxies, including our own Milky Way, contain huge amounts of cold dust that absorbs visible light and these dusty regions just look black when seen through an optical telescope. The absorbed energy is then re-radiated by the dust at longer, submillimetre, wavelengths", explains Professor Gary Davis, Director of the JCMT. "SCUBA-2 has been designed to detect extremely low energy radiation in the submillimetre region of the spectrum. To do this, the instrument itself needs to be even colder. The detectors inside SCUBA-2 have to be cooled to only 0.1 degree above absolute zero [–273.05°C], making the interior of SCUBA-2 colder than anything in the Universe that we know of!"

The project was led by STFC's UK Astronomy Technology Centre (UKATC) in Edinburgh in collaboration with a world-wide consortium of laboratories including four universities (British Columbia, Cardiff, Edinburgh and Waterloo), the US National Institute of Standards and Technology, and the Joint Astronomy Centre, which operates the James Clerk Maxwell Telescope.

Professor Ian Robson, Director of UKATC, said: "The heart of SCUBA-2, the detector arrays, are a huge achievement; a world-first and the technological challenges in making them have been absolutely immense. It is equivalent to going from a primitive wind-on film camera that people over 50 might remember using straight to a modern digital camera all in one step. It is thanks to the ingenuity and abilities of our scientists and engineers that this immense leap in progress has been achieved."

UK, Canadian and Dutch researchers have pioneered observations of the sky in the submillimetre wavelength range (0.4 to 1 millimetre) through their partnership on the James Clerk Maxwell Telescope. SCUBA-2's predecessor, SCUBA (Submillimetre Common User Bolometer Array) produced many new and unexpected discoveries, from a previously unknown population of distant, dusty galaxies (known ever since as 'SCUBA galaxies'), to the first images of cold debris discs around nearby stars, which may indicate the presence of planetary systems.

Commenting on the performance of the new instrument, Professor Wayne Holland of UKATC, and the SCUBA-2 Project Scientist, said: "With SCUBA, it typically took 20 nights to image an area about the size of the full Moon. SCUBA-2 will be able to cover the same area in a couple of hours and go much deeper, allowing us to detect faint objects that have never been seen before."

The increased mapping speed and sensitivity of SCUBA-2 make it ideal for large-scale surveys; no other instrument will be able to survey the submillimetre sky in such exquisite detail. Dr Antonio Chrysostomou, Associate Director of the JCMT said: "SCUBA-2's first task will be to carry out a series of surveys right across the heavens, mapping sites of star formation within our Galaxy, as well as planet formation around nearby stars. It will also survey our galactic neighbours and crucially, will look deep into space and sample the youngest galaxies in the Universe, which will be critical to understanding how galaxies have evolved since the Big Bang."

The data obtained by these surveys will allow a new and precise understanding of star formation throughout the history of the universe, and complements research being carried out on other telescopes such as the Atacama Large Millimetre Array (ALMA), currently undergoing commissioning in Chile.

Notes to editors

Media contacts

Stephanie Hills
STFC Media Manager
Tel: +44 (0)1235 445 398

Dr Holly Thomas
Joint Astronomy Centre
Tel: +1 808 969 6531
Fax: +1 808 961 6516

Dr John Davies
STFC UK Astronomy Technology Centre
Tel: +44 (0)131 668 8348

Science Contacts

Please note that it is best to contact these individuals by email.
Prof Wayne Holland
STFC UK Astronomy Technology Centre
Tel: +44 (0)131 668 8389

Prof Ian Robson
UK Astronomy Technology Centre
Tel: +44 (0)131 668 8438

Dr Antonio Chrysostomou
Joint Astronomy Centre
Tel: +1 808 969 6512

Prof Gary Davis
Joint Astronomy Centre
Tel: +1 808 969 6504

Further information

Light Year

One light year is about 10 million million kilometres or 6 million million miles.

Submillimetre Light

Submillimetre wavelengths are much smaller wavelengths than emitted by a typical radio station, but longer wavelengths than light waves or infrared wavelengths.

They are typically measured in microns, also called micrometres. One micron is one millionth of a metre or one 10,000th of a centimetre.

Submillimetre astronomy is most sensitive to very cold gas and dust. For example, a source with a temperature of 10 K (–263°C) emits most of its energy in a broad spectral region centred around 300 microns. Such very cold material is associated with objects in formation, that is, the mysterious earliest evolutionary stages of galaxies, stars and planets. To understand the origins of these most fundamental of astronomical structures, the submillimetre is the waveband of choice.

SCUBA-2 key facts

Size: 3m (height), 2.4m (width), 2.6m (depth)
Weight: 4.5 tonnes (about three times the weight of a typical car)
Temperature of detectors: 0.1K = –272.9°C = –459.2°F
Submillimetre camera with 5120 pixels (4 sub arrays x 1280 pixels) at each wavelength band
Provides a unique wide-field submillimetre imaging capability at 450 and 850 microns
Hundreds of times faster at mapping large areas of sky than predecessor SCUBA to the same signal-to-noise
Uses superconducting transition edge sensors as the light-sensitive elements
Addresses a wide-range of scientific issues including how galaxies, stars and planets form
Acts as a wide-field "pathfinder" for the new generation of submillimetre interferometers (e.g. SMA and ALMA)

The SCUBA-2 project is a collaboration of several observatories or laboratories. The project was led by the UK Astronomy Technology Centre (UK ATC) with the partners:
University of Edinburgh (array structures)
Cardiff University (Focal Plane Units and 1K enclosure)
US National Institute of Standards and Technology (detector arrays and readout)
University of British Columbia, Canada (multi-channel electronics and data reduction software)
University of Waterloo, Canada (multiplexer screening)
Joint Astronomy Centre (infrastructure and software)

A 2001 survey by the US-based Space Telescope Science Institute revealed that scientific results from SCUBA-2's predecessor, SCUBA had been cited almost as often as those from the Hubble Space Telescope, and much more so than those from any other ground-based facility or satellite project.

The project was funded by the Science and Technology Facilities Council (STFC), the JAC, and the Canada Foundation for Innovation.
The UK ATC SCUBA-2 webpage (link opens in a new window)

James Clerk Maxwell Telescope

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 Science and Technology Facilities Council, the Canadian National Research Council, and the Netherlands Organisation for Scientific Research.
More about the James Clerk Maxwell Telescope
(link opens in a new window)

About National Research Council Canada

Recognized globally for research and innovation, Canada's NRC is a leader in the development of an innovative, knowledge-based economy for Canada through science and technology.
Netherlands Organisation for Scientific Research

The Netherlands Organisation for Scientific Research(NWO) is the principal Dutch science funding body and its mission is to facilitate excellent scientific research in the Netherlands by means of national competition. Each year NWO spends more than 700 million euros on grants for top research and top researchers, on innovative instruments and equipment, and on institutes where top research is performed. NWO funds the research of more than 5300 talented researchers at universities and institutes. Independent experts select proposals by means of a peer review system. NWO facilitates the transfer of knowledge to society.

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