Massive molecular cloud cores and activities of star formation

We have mapped 23 sources in the J=1--0 lines of ¹²CO, ¹³CO and C¹⁸O with the 13.7-m telescope at Qinghai station of Purple Mountain Observatory.The samples were chosen from the massive star formation regions whose single point lines have the broad-wing profile. The mapping shows that 12 clouds have cores and 5 outflows were identified with the ¹²CO CO J=1--0 lines. Among the 12 cores, systematic velocity shifts were found in 2 cores, and blue asymmetric double-peak profile of ¹²CO line was found in IRAS 19529+2704, indicating that it may be an infall candidate. Physical parameters of the cores and outflows were derived from the local thermodynamic equilibrium assumption.The masses range from \sim 9.4\times 10^2M_\odot to \sim 2.2\times 10^5M_ \odot . The hydrogen molecule densities range from \sim3.4\times10^2 cm^-3 to \sim 1.2\times 10^4 cm^-3. The molecular outflows have masses larger than 3.5M_ \odot , and kinetic energies greater than 0.9\times10³⁸J. The outflows have significantly greater masses and kinetic energies than those from low-mass young stellar objects (YSOs). For the cores, 2MASS data are available, dozens of 2MASS sources with different colour indices and brightness are often found around IRAS source, among which the reddest 2MASS source is always within the IRAS error ellipse thus probably corresponds to the IRAS source.