  We observed the clustered star forming complex NGC1333 with the BIMA and
FCRAO telescopes in the transitions HCO+(1-0) and N2H+(1-0) over an 11'x11'
area with resolution ~10" (0.015pc). The N2H+ emission follows very closely the
submillimeter dust continuum emission, while HCO+ emission appears more
spatially extended and also traces outflows. We have identified 93 N2H+ cores
using the CLUMPFIND algorithm, and we derive N2H+ core masses between 0.05 and
2.5M_sun, with uncertainties of a factor of a few, dominated by the adopted
N2H+ abundance. From a comparison with virial masses, we argue that most of
these N2H+ cores are likely to be bound, even at the lowest masses, suggesting
that the cores do not trace transient structures, and implies the entire mass
distribution consists of objects that can potentially form stars. We find that
the mass distribution of N2H+ cores resembles the field star IMF, which
suggests that the IMF is locked in at the pre-stellar stage of evolution. We
find that the N2H+ cores associated with stars identified from Spitzer infrared
images have a flat mass distribution. This might be because lower mass cores
lose a larger fraction of their mass when forming a star. Even in this
clustered environment, we find no evidence for ballistic motions of the cores
relative to their lower density surroundings traced by isotopic CO emission,
though this conclusion must remain tentative until the surroundings are
observed at the same high resolution as the N2H+.

Astrophysics