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FOR IMMEDIATE RELEASE:

Dr Holly Thomas
Joint Astronomy Centre
Email: h.thomas@jach.hawaii.edu
Desk: +1 808 969 6531
JAC Main: +1 808 961 3756

Images, notes, and contact details appear below.

17th April 2012


Dusty Stellar Nurseries from the Dark Side of a Galaxy

A new multi-million pound camera is producing its first detailed pictures of our neighboring galaxies, revealing vast, dusty stellar nurseries where the next generation of stars is being created. "This exquisite image from the galaxy M66 in the constellation Leo is exactly the promising start we were hoping for," said Dr. Stephen Serjeant, the team's co-leader from The Open University. "This is a wonderfully exciting taste of things to come."

When looking up at the Milky Way, an irregular pattern of dark regions obscures the light of the stars. The dark patches are caused by clouds of dust trailing through the spiral arms and blocking out the starlight; they contain vast stellar nurseries where the next generation of stars is being created. These dark lanes are not exclusive to the Milky Way, but can be found in all spiral galaxies.

Although they are dark to our eyes, these dust lanes actually glow brightly at sub-millimetre (sub-mm) wavelengths. A revolutionary new camera, called SCUBA-2, is ideally suited to detect this long-wavelength dust emission. It is mounted on the world's largest sub-mm telescope, the 15-metre James Clerk Maxwell Telescope (JCMT) in Hawaii, and is the most powerful camera ever developed for observing sub-mm wavelengths. It detects light waves 1000 times longer than human eyes can see.

This image promises to be the first of many stunning results from the JCMT Nearby Galaxy Legacy Survey (NGLS). The main aim of the survey is to understand how the broader environment of a galaxy affects its gas and dust content. For example, galaxies in dense clusters can lose their gas and dust through interactions with other galaxies in the cluster or simply by the head wind they feel while moving through the hot gas trapped inside the cluster. The NGLS is an international collaboration led by astronomers from Canada, the Netherlands, and the United Kingdom which is using SCUBA-2 to observe 150 galaxies in the local universe.

The NGLS team has spent much of the last five years studying molecular hydrogen emission using another instrument on the JCMT. "It is very exciting to now see the first results from the SCUBA-2 side of our program starting to come in," says Professor Christine Wilson, the Principal Investigator from McMaster University in Canada. "We have a unique sample of galaxies that we are studying and having SCUBA-2 data will let us measure their gas and dust content. Gas and dust usually go hand-in-hand in galaxies, but from time to time, you find a surprise."


Images

The red colors in this image show the galaxy M66 as it appears at the sub-mm wavelength of 850 microns, while the white background shows the galaxy as it appears in visible light. Regions of cold dust that appear as dark streaks in the white image glow brightly in the red image. The center of the galaxy contains much more dust than is obvious from looking at the visible image and the sub-mm image also picks out an unusual compact cloud in the southern part of the galaxy that is a prime site for future star formation.
Credit: VLT/ESO, JAC, G. Bendo
Full size image
(JPG, 1.3MB)

Left-hand panel: The red colors in this image show the galaxy M66 as it appears at the sub-mm wavelength of 850 microns, while the white background shows the galaxy as it appears in visible light. Regions of cold dust that appear as dark streaks in the white image glow brightly in the red image. Right-hand panel: The SCUBA-2 image at 850 microns seen on its own.
Credit: VLT/ESO, JAC, G. Bendo
Full size image (JPG, 1.5MB)

The James Clerk Maxwell Telescope is situated at 14,000 feet atop Mauna Kea in Hawaii.
Credit: Nik Szymanek.
Full size image (JPG, 1.5MB)


Notes

Sub-millimetre Light

Sub-millimetre 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, one 10,000th of a centimetre, or one 25,000th of an inch.

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. If one wants 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)
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 Joint Astronomy Centre (JAC), and the Canada Foundation for Innovation (CFI).

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.
The JCMT webpage can be found at http://www.jach.hawaii.edu/JCMT/

McMaster University

The McMaster Physics and Astronomy webpage can be found at www.physics.mcmaster.ca.

The Open University

The Open University Physical Sciences webpage can be found at www8.open.ac.uk/science/physical-science

Leiden Observatory

The Leiden Observatory webpage can be found at www.strw.leidenuniv.nl


Media Contacts

Please note that it is best to contact these individuals by email.

  • Stephanie Hills
    STFC Media Manager
    Desk: +44 (0)1235 445398
    Email: stephanie.hills@stfc.ac.uk

  • Dr Holly Thomas
    Joint Astronomy Centre
    Desk: +1 808-969-6531
    Fax: +1 808-961-6516
    Email: h.thomas@jach.hawaii.edu

Science Contacts

Please note that it is best to contact these individuals by email.

  • Prof. Christine Wilson (NGLS PI)
    Department of Physics and Astronomy,
    McMaster University,
    Hamilton, Ontario, L8S 4M1
    Canada
    Tel: 1 905 525 9140 (ext)27483
    email: wilson@physics.mcmaster.ca

  • Dr Stephen Serjeant
    Head of Astronomy,
    The Open University,
    Milton Keynes, MK7 6AA, UK
    Tel: +44 (0)1908 652724
    Mob: +44 (0)7946 605913
    email: s.serjeant@open.ac.uk

  • Dr Antonio Chrysostomou
    Associate Director, JCMT
    Joint Astronomy Centre
    Desk: +1 808-969-6512
    Email: a.chrysostomou@jach.hawaii.edu

Contact: JAC outreach. Updated: Wed Apr 18 17:19:08 HST 2012

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