  Stars form in 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 recently approved by the JCMT Board. Starting in 2007,
the SLS will produce a spectral imaging survey of the content and distribution
of all the molecules detected in the 345 GHz atmospheric window (between 332
GHz and 373 GHz) towards a sample of 5 sources. Our intended targets are: a low
mass core (NGC1333 IRAS4), 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.
