A Sensitive Survey of Dense Parts of Outflows toward Massive Cores

A set of samples of 13 massive star-forming cores were observed in SiO (2-1), CH3OH (2-1) and C34S (2-1) thermal lines. Nine of these cores were detected in all three lines. Among the nine SiO detections, three were new detections, and relatively faint. Most of the lines have wide wings, which might be interpreted as the evidence of ongoing energetic outflows in the cores. The line widths of SiO are generally the broadest, which might further suggest that the SiO emissions are due to higher velocity outflow, and closer to the excited source. We derive the rotational temperatures, column densities and chemical relative abundances of the cores. There is a strong correlation between SiO and CH3OH abundances, with correlation coeffcient R = 0.77, but no correlation is observed between SiO and C34S.