  Molecular outflows provide an alternative method of identifying protostellar
cores, complementary to recent mid-infrared studies. Continuing our studies of
Perseus, we investigate whether all Spitzer-identified protostars, and
particularly those with low luminosities, drive outflows, and if any new
protostellar cores (perhaps harbouring low-mass sources) can be identified via
their outflows alone. We have used the heterodyne array receiver HARP on JCMT
to make deep 12CO 3-2 maps of submm cores in Perseus, extending and deepening
our earlier study with RxB and bringing the total number of SCUBA cores studied
up to 83. Our survey includes 23/25 of the Dunham et al. (2008) Spitzer
low-luminosity objects believed to be embedded protostars, including three
VeLLOs. All but one of the cores identified as harbouring embedded YSOs have
outflows, confirming outflow detections as a good method for identifying
protostars. We detect outflows from 20 Spitzer low-luminosity objects. We do
not conclusively detect any outflows from IR-quiet cores, though confusion in
clustered regions such as NGC1333 makes it impossible to identify all the
individual driving sources. This similarity in detection rates despite the
difference in search methods and detection limits suggests either that the
sample of protostars in Perseus is now complete, or that the existence of an
outflow contributes to the Spitzer detectability, perhaps through the
contribution of shocked H2 emission in the IRAC bands. For five of the
low-luminosity sources, there is no protostellar envelope detected at 350
microns and the Spitzer emission is entirely due to shocks. Additionally, we
detect the outflow from IRAS 03282+3035 at 850 microns with SCUBA due to CO
line contamination in the continuum passband.
