High-sensitivity Millimeter Imaging of Molecular Outflows in Nine Nearby High-mass Star-forming Regions

Abstract

Abstract We present a study of molecular outflows using six molecular lines (including 12CO/13CO/C18O/HCO+ (J = 1−0) and CS/SiO (J = 2−1)) toward nine nearby high-mass star-forming regions with accurate known distances. This work is based on the high-sensitivity observations obtained with the 14 m millimeter telescope of the Purple Mountain Observatory in Delingha. The detection rate of outflows (including 12CO, 13CO, HCO+, and CS) is 100%. However, the emission of SiO was not detected for all sources. The full line widths (ΔV) at 3σ above the baseline of these molecular lines have the relationship > . 12CO and HCO+ can be used to trace relatively high-velocity outflows, while 13CO and CS can be employed to trace relatively low-velocity outflows. The dynamical timescales of the 13CO and CS outflows are longer than those of the 12CO and HCO+ outflows. The mechanical luminosities, masses, mass-loss rates and forces of all outflows (including 12CO, 13CO, HCO+, and CS) are correlated with the bolometric luminosities of their central IRAS sources.