Astronomers using the James Clerk Maxwell Telescope (JCMT) in Hawaii are making new discoveries about the origins of the planets, stars and galaxies with the start of a new survey to map the Universe.
The JCMT Legacy Survey, made up of 7 projects, makes use of two sophisticated new instruments - SCUBA-2 and HARP – which will allow the astronomers to detect and probe clouds of cold dust associated with the mysterious earliest phases of the formation of galaxies, stars and planets.
SCUBA-2 is a powerful camera capable of mapping regions of the sky by detecting the heat emitted by this extremely cold dust. It has recently been delivered to the JCMT and is under commission. When completed it will have the ability to pinpoint and image many hundreds of distant, dust enshrouded galaxies in a single night.
Many of these galaxies are among the earliest structures observable in the universe and are largely undetectable by other telescopes. The Harp instrument allows astronomers to see the motion of this gas with clarity and precision and has the powerful ability to record information in three dimensions.
The UK’s Science and Technology Facilities Council (STFC) jointly owns and operates the JCMT and much of the design and construction of the telescope and the existing and future instrumentation, including SCUBA-2 and HARP, has been undertaken by groups in the UK, in particular STFC’s UK Astronomy and Technology Centre and the Universities of Wales, Cardiff and Edinburgh.
Projects already underway include the Nearby Galaxies Legacy Survey, the Gould Belt Survey and the Spectral Legacy Survey. All 3 of these projects use the HARP instrument.
The Nearby Galaxies Legacy Survey aims to produce the first large sample of galaxies close to our own (within 81,500,000 light years). The data will help us to better understand the properties of the matter that exists between the stars in these galaxies, how it is affected by its environment, and how it compares with our Galaxy.
Professor Christine Wilson from McMaster University, Canada, who leads the project, said: "It has been very exciting over the last year to go from verifying the performance of HARP/ACSIS on the JCMT to completing over 80% of our HARP survey. We have been kept very busy processing the flood of data that is being produced, but the reward has been seeing all these beautiful images of nearby galaxies appearing one by one. It simply would not have been possible to obtain so many large and sensitive images of our galactic neighbours without HARP/ACSIS. We are using these new data from the Nearby Galaxy Legacy Survey to map out how the dense gas, which is the fuel for forming new stars, is distributed in galaxies with different masses and environments.One of our exciting results is to be able to map, for the first time, how efficiently gas is being turned into stars from one region of a galaxy to another."
Closer to home, a complete survey of star formation within 1,630 light years of our Sun is the aim of the Gould Belt Survey (so-called for the belt of star forming clouds encircling our Sun), a project led by Dr Jennifer Hatchell at the University of Exeter. The JCMT and its instruments are well suited for studies of star formation as it is only at these long wavelengths that we are able to probe into the coldest, densest regions of clouds where stars are actively forming.
Dr Hatchell says: "The maps coming out of HARP are larger and better quality than anything we had to work with before. Now we can see just how much the gas clouds are being moved about by the newly-forming stars inside them."
The sensitive observations that the JCMT can provide will give astronomers a better understanding of the processes required to form stars and a clearer idea of how often and efficiently this happens.
Professor Derek Ward-Thompson from Cardiff University said: "These HARP images allow us to see a three-dimensional picture of star birth in molecular clouds. It shows just what a violent process star birth is - in fact almost as violent as a star's death."
The details of the star formation process are to be provided by the Spectral Legacy Survey. This survey team will obtain a chemical inventory of star formation in a sample carefully selected to span different evolutionary stages of development.
Dr John Richer from Cambridge University said: "We've never made images like these before. With previous instruments, the maps would have taken too long to make - several weeks or so. But in only eight hours of observing, HARP has generated incredible new images which for the first time reveal the fine details of star formation."
"We have been preparing for the JCMT Legacy Survey for several years", says Professor Gary Davis, the Director of the JCMT. "This is the culmination of a process in which astronomers in the UK, Canada and the Netherlands came together to define a unified and comprehensive survey of the submillimetre sky. This has never been done before because the revolutionary instruments required to do it have not, until now, been available. The survey programme is of the highest scientific calibre and will have far-reaching effects on all areas of astrophysics. The spectacular results so far are just a tantalising hint of what is yet to come."
The JCMT Legacy Survey is also actively being used by the teams of researchers as a fertile training ground for future astronomers.
Robert Simpson, a PhD student from Cardiff University, UK, says: "The images produced by HARP have smashed my old notions of the beautiful and serene nebula. As a kid I always thought nebulae were so gentle and elegant, but images such as these reveal the violence and energy flowing inside them. I've seen the equations and I've read the theory, but these images show you the physics behind star formation in a better, more intuitive way. Working on HARP data during my PhD has given me a new insight into star formation and has changed my perspective. What more can you ask for from science?"