We present a census of molecular outflows across four active regions of star formation in the Perseus molecular cloud (NGC 1333, IC348/HH211, L1448 and L1455), totalling an area of over 1000 arcmin 2 . This is one of the largest surveys of outflow evolution in a single molecular cloud published to date. We analyse large-scale, sensitive CO J = 3 → 2 data sets from the James Clerk Maxwell Telescope, including new data towards NGC 1333. Where possible we make use of our complementary 13 CO and C 18 O data to correct for the 12 CO optical depth and measure ambient cloud properties. Of the 65 submillimetre cores in our fields, we detect outflows towards 45. 24 of these are marginal detections where the outflow's shape is unclear or could be confused with the other outflows. We compare various parameters between the outflows from Class 0 and I protostars, including their mass, momentum, energy and momentum flux. Class 0 outflows are longer, faster, more massive and have more energy than Class I outflows. The dynamical time-scales we derive from these outflows are uncorrelated to the age of the outflow driving source, computed from the protostar's bolometric temperature. We confirm the results of Bontemps et al. that outflows decrease in force as they age. There is a decrease in momentum flux from the Class 0 to I stage: F CO = (0.8 ± 0.3) × 10 −4 compared to (1.1 ± 0.3) × 10 −5 M km s −1 yr −1 , suggesting a decline in the mass accretion rate assuming the same entrainment fraction for both classes of outflow. If F rad = L bol /c is the flux expected in radiation from the central source, then F CO (Class I) ∼ 100F rad and F CO (Class 0) ∼ 1000F rad . Furthermore, we confirm there are additional sources of mass loss from protostars. If a core's mass is only lost from outflows at the current rate, cores would endure a few million years, much longer than current estimates for the duration of the protostellar stage. Finally, we note that the total energy contained in outflows in NGC 1333, L1448 and L1455 is greater than the estimated turbulent energy in the respective regions, which may have implications for the regions' evolution.

This paper describes a new Heterodyne Array Receiver Program (HARP) and Auto‐Correlation Spectral Imaging System (ACSIS) that have recently been installed and commissioned on the James Clerk Maxwell Telescope. The 16‐element focal‐plane array receiver, operating in the submillimetre from 325 to 375 GHz, offers high (three‐dimensional) mapping speeds, along with significant improvements over single‐detector counterparts in calibration and image quality. Receiver temperatures are ∼120 K across the whole band, and system temperatures of ∼300 K are reached routinely under good weather conditions. The system includes a single‐sideband (SSB) filter so these are SSB values. Used in conjunction with ACSIS, the system can produce large‐scale maps rapidly, in one or more frequency settings, at high spatial and spectral resolution. Fully sampled maps of size can be observed in under 1 h. The scientific need for array receivers arises from the requirement for programmes to study samples of objects of statistically significant size, in large‐scale unbiased surveys of galactic and extra‐galactic regions. Along with morphological information, the new spectral imaging system can be used to study the physical and chemical properties of regions of interest. Its three‐dimensional imaging capabilities are critical for research into turbulence and dynamics. In addition, HARP/ACSIS will provide highly complementary science programmes to wide‐field continuum studies and produce the essential preparatory work for submillimetre interferometers such as the Submillimeter Array (SMA) and Atacama Large Millimeter/Submillimeter Array (ALMA).

We present submillimetre observations of the J = 3 → 2 rotational transition of 12 CO, 13 CO and C 18 O across over 600 arcmin 2 of the Perseus molecular cloud, undertaken with the Heterodyne Array Receiver Programme (HARP), a new array spectrograph on the James Clerk Maxwell Telescope. The data encompass four regions of the cloud, containing the largest clusters of dust continuum condensations: NGC 1333, IC348, L1448 and L1455. A new procedure to remove striping artefacts from the raw HARP data is introduced. We compare the maps to those of the dust continuum emission mapped with the Submillimetre Common-User Bolometer Array (SCUBA; Hatchell et al.) and the positions of starless and protostellar cores (Hatchell et al.). No straightforward correlation is found between the masses of each region derived from the HARP CO and SCUBA data, underlining the care that must be exercised when comparing masses of the same object derived from different tracers. From the 13 CO/C 18 O line ratio the relative abundance of the two species ([ 13 CO]/[C 18 O] ∼ 7) and their opacities (typically τ is 0.02-0.22 and 0.15-1.52 for the C 18 O and 13 CO gas, respectively) are calculated. C 18 O is optically thin nearly everywhere, increasing in opacity towards star-forming cores but not beyond τ 18 ∼ 0.9. Assuming the 12 CO gas is optically thick, we compute its excitation temperature, T ex (around 8-30 K), which has little correlation with estimates of the dust temperature.

We present observations of NGC 1333 from SCUBA-2 on the James Clerk Maxwell Telescope (JCMT), observed as a JCMT Gould Belt Survey pilot project during the shared risk campaign when the first of four arrays was installed at each of 450 and 850 μm. Temperature maps are derived from 450 and 850 μm ratios under the assumption of constant dust opacity spectral index β = 1.8. Temperatures indicate that the dust in the northern (IRAS 6/8) region of NGC 1333 is hot, 20–40 K, due to heating by the B star SVS3, other young stars in the IR/optically visible cluster and embedded protostars. Other luminous protostars are also identified by temperature rises at the 17 arcsec resolution of the ratio maps (0.02 pc assuming a distance of 250 pc for Perseus). The extensive heating raises the possibility that the radiative feedback may lead to increased masses for the next generation of stars.

This paper describes a James Clerk Maxwell Telescope (JCMT) legacy survey that has been awarded roughly 500 hrs of observing time to be carried out from 2007 to 2009. In this survey we will map with SCUBA-2 (Submillimetre Common User Bolometer Array 2) almost all of the well-known low-mass and intermediate-mass star-forming regions within 0.5 kpc that are accessible from the JCMT. Most of these locations are associated with the Gould Belt. From these observations we will produce a flux-limited snapshot of star formation near the Sun, providing a legacy of images, as well as point-source and extended-source catalogues, over almost 700 square degrees of sky. The resulting images will yield the first catalogue of prestellar and protostellar sources selected by submillimetre continuum emission, and should increase the number of known sources by more than an order of magnitude. We will also obtain CO maps with the array receiver HARP (Heterodyne Array Receiver Programme), in three CO isotopologues, of a large typical sample of prestellar and protostellar sources. We will then map the brightest hundred sources with the SCUBA-2 polarimeter (POL-2), producing the first statistically significant set of polarization maps in the submillimetre. The images and source catalogues will be a powerful reference set for astronomers, providing a detailed legacy archive for future telescopes, including ALMA, Herschel and JWST.Subject headings: ISM