The TOP-SCOPE survey of PGCCs: PMO and SCUBA-2 observations of 64 PGCCs in the 2nd Galactic Quadrant

Abstract

In order to understand the initial conditions and early evolution of star formation in a wide range of Galactic environments, we carried out an investigation of 64 \textit{Planck} Galactic Cold Clumps (PGCCs) in the second quadrant of the Milky Way. Using the ${}^{13}$CO and C${}^{18}$O $J=1-0$ lines, and 850\,$\hat{I}¼$m continuum observations, we investigated cloud fragmentation and evolution associated with star formation. We extracted 468 clumps and 117 cores from the ${}^{13}$CO line and 850\,$\hat{I}¼$m continuum maps, respectively. We make use of the Bayesian Distance Calculator and derived the distances of all 64 PGCCs. We found that in general, the mass-size plane follows a relation of $m\sim r^{1.67}$. At a given scale, the masses of our objects are around 1/10 of that of typical Galactic massive star-forming regions. Analysis of the clump and core masses, virial parameters, densities, and mass-size relation suggests that the PGCCs in our sample have a low core formation efficiency ($\sim$3.0\%), and most PGCCs are likely low-mass star-forming candidates. Statistical study indicates that the 850\,$\hat{I}¼$m cores are more turbulent, more optically thick, and denser than the ${}^{13}$CO clumps for star formation candidates, suggesting that the 850\,$\hat{I}¼$m cores are likely more appropriate future star-formation candidates than the ${}^{13}$CO clumps.

51 pages, 13 figures, 5 tables; Accepted for publication in ApJS; Supplementary figures can be downloaded in https://zcp521.github.io/pub/Figs.zip