JCMT Legacy Surveys

The JCMT Legacy Survey:

The JCMT Legacy Surveys (JLS) is an ambitious programme to study out Galaxy and Universe in the submillimetre using the James Clerk Maxwell telescope at the summit of Mauna Kea in Hawaii. It comprises of seven programmes whose scientific objectives are to understand the origina, nature and evolution of the universe, galaxies, stars and planets.

The seven programmes which make up the JLS are given below. Follow the links to read short summary descriptions of the science cases and other survey specific information.

The SCUBA-2 "All Sky" Survey (SASSy)
The SCUBA-2 Cosmology Legacy Survey (CLS)
The Nearby Galaxies Survey (NGS)
The JCMT Galactic Plane Survey (JPS)
The Gould Belt Survey (GBS)
The Spectral Legacy Survey (SLS)
The Debris Disk Survey (DDS)

The University of Calgary's Role in the JCMT Legacy Survey:

Dr. Plume is the Canadian coordinator for two of the JCMT Legacy Surveys: The Galactic Plane Survey and the Spectral Legacy Survey.

The Galactic Plane Survey:

The current big questions in star formation are largely centered on the the processes related to high-mass and large-scale star formation, since it is high-mass stars that produce the powerful feedback into the star-formation process and into the processing of the interstellar medium. Specifically, progress in the field demands an understanding of: the variation in the star formation efficiency and its relationship to the strength of triggering mechanisms; the origin of the stellar initial mass function, the degree to which it varies and its relationship to the mass function of structures in molecular clouds; the formation and evolution of stellar clusters and their relationship to high-mass star formation; the distinction between spontaneous and induced (or triggered) star formation; the problem of rapid accretion rates and the nature of the high-mass star-formation process; the evolution of high-mass YSOs and the reliable identification of evolutionary stages; the nature of molecular clouds, their support and the initial conditions for star-formation; the effect of environment and magnetic fields on the star-formation process.

All these questions can be addressed only by assembling representative samples of star-forming regions, YSOs, molecular cloud complexes, cold diffuse clouds, and the ambient interstellar medium with which these object interact. The JCMT Galactic Plane Survey (JPS) will provide the means to answer these key questions in massive star formation by examining all stages of the process and all the significant mechanisms operating on scales from dense cores to that of the whole Galaxy. The sample size and vast range of environments will place massive star formation research onto a firm statistical basis for the first time. This will allow the most exhaustive investigation into the physics that determines the upper IMF that can be undertaken in a spiral galaxy from our unique close-up vantage point. The knowledge gained from such a survey will have far-reaching benefits for the whole of astrophysics.

The Spectral Legacy Survey:

Stars from the densest, coldest, most quiescent regions of molecular clouds. Molecules provide the only probes which can reveal the dynamics, physics, chemistry and evolution of these regions, but our understanding of the molecular inventory of sources and how this is related to their physical state and evolution is rudimentary and incomplete. The Spectral Legacy Survey (SLS) is one of seven surveys approved by the JCMT Board. Starting in 2007, the SLS will produce a specral imaging survey of the content and distribution of all the molucules detected in the 345 GHz atmospheric window (between 332 GHz and 373 GHz), 3 high mass cores spanning a range of star forming environments and evolutionary states (W49, AFGL2591, and IRAS20126), and a PDR (the Orion Bar). The SLS will use the unique spectral imaging capabilities of HARP-B/ACSIS to study the molecular inventory and the physical structure of these objects, which span different evolutionary stages and physical environments, to probe their evolution during the star formation process. As its name suggests, the SLS will provide a lasting data legacy from the JCMT that is intended to benefit the entire astronomical community. As such, the entire data set (including calibrated spectral datacubes, maps of molecular emission, line identifications, and calculations of the gas temperature and column density) will be publicly available.

Links:

James Clerk Maxwell telescope (JCMT): http://www.jach.hawaii.edu/JCMT
JCMT Legacy Survey Page: http://www.jach.hawaii.edu/JCMT/surveys/