The properties of Planck Galactic cold clumps in the L1495 dark cloud
  Planck Galactic Cold Clumps (PGCCs) possibly represent the early stages of
star formation. To understand better the properties of PGCCs, we studied 16
PGCCs in the L1495 cloud with molecular lines and continuum data from Herschel,
JCMT/SCUBA-2 and the PMO 13.7 m telescope. Thirty dense cores were identified
in 16 PGCCs from 2-D Gaussian fitting. The dense cores have dust temperatures
of $T_{\rm d}$ = 11-14 K, and H$_{2}$ column densities of $N_{\rm H_{2}}$ =
0.36-2.5$\times10^{22}$ cm$^{-2}$. We found that not all PGCCs contain
prestellar objects. In general, the dense cores in PGCCs are usually at their
earliest evolutionary stages. All the dense cores have non-thermal velocity
dispersions larger than the thermal velocity dispersions from molecular line
data, suggesting that the dense cores may be turbulence-dominated. We have
calculated the virial parameter $\alpha$ and found that 14 of the dense cores
have $\alpha$ $<$ 2, while 16 of the dense cores have $\alpha$ $>$ 2. This
suggests that some of the dense cores are not bound in the absence of external
pressure and magnetic fields. The column density profiles of dense cores were
fitted. The sizes of the flat regions and core radii decrease with the
evolution of dense cores. CO depletion was found to occur in all the dense
cores, but is more significant in prestellar core candidates than in
protostellar or starless cores. The protostellar cores inside the PGCCs are
still at a very early evolutionary stage, sharing similar physical and chemical
properties with the prestellar core candidates.
