Massive molecular cloud cores and activities of star formation

• 来源期刊: 中国物理（英文版）
• 关键词: Interstellar matter molecular cloud star formation
• 年，卷（期）: 2005,（4）
• 页码范围: 863-868
• 页数: 6页
• 语种: 英文

摘要

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 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 ～ 9.4 × 102M⊙ to ～ 2.2 × 105M⊙. The hydrogen molecule densities range from ～ 3.4 × 102cm-3 to～ 1.2 × 104cm-3. The molecular outflows have masses larger than 3.5M⊙, and kinetic energies greater than 0.9× 1038J.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.