The JCMT Gould Belt Survey Complete Core Catalogue: Core mass function variations between nearby molecular clouds

Abstract

We present a catalogue of dense cores identified in James Clerk Maxwell Telescope (JCMT) Gould Belt Survey SCUBA-2 observations of nearby star-forming clouds. We identified 2257 dense cores using the getsources algorithm, of which 59% are starless, and 41% are potentially protostellar. 71% of the starless cores are prestellar core candidates, suggesting a prestellar core lifetime similar to that of Class 0/I YSOs. Higher-mass clouds have a higher fraction of prestellar cores compared to protostars, suggesting a longer average prestellar core lifetime. We assessed completeness by inserting critically-stable Bonnor– Ebert spheres into a blank SCUBA-2 field: completeness scales as distance squared, with an average mass recovery fraction of 73 ± 6% for recovered sources. We calculated core masses and radii, and assessed their gravitational stability using the Bonnor–Ebert criterion. Maximum starless core mass scales with cloud complex mass with an index 0.58 ± 0.13, consistent with the behaviour of maximum stellar masses in embedded clusters. We performed least-squares and Monte Carlo modelling of the core mass functions (CMFs) of our starless and prestellar core samples. The CMFs can be characterised using log-normal distributions: we do not sample the full range of core masses needed to create the stellar Initial Mass Function (IMF). The CMFs of the clouds are not consistent with being drawn from a single underlying distribution. The peak mass of the starless core CMF increases with cloud mass; the prestellar CMF of the more distant clouds has a peak mass ∼3 × the log-normal peak for the system IMF, implying a ∼33% prestellar core-to-star efficiency.