Thirty massive clumps associated with bright infrared sources were observed to detect the infall signatures and characterize infall properties in the envelope of the massive clumps by APEX telescope in CO(4–3) and C¹⁷O(3–2) lines. Eighteen objects exhibit a “blue profile” in the CO(4–3) line with virial parameters less than 2, suggesting that global collapse is taking place in these massive clumps. The CO(4–3) lines were fitted via the two-layer model in order to obtain infall velocities and mass infall rates. Derived mass infall rates range from 10⁻³ to 10⁻¹ M _⊙ yr⁻¹. A positive relationship between clump mass and infall rate appears to indicate that gravity plays a dominant role in the collapsing process. Higher luminosity clumps have a larger mass infall rate, implying that those clumps with higher mass infall rates possess a higher star formation rate.

^{通过 APEX 望远镜在 CO(4-3) 和 C 17} O(3-2) 线中观察到与明亮的红外源相关的 30 个大块团块，以检测入流特征并表征大块团块包络中的入流特性。18 个物体在 CO(4-3) 线上表现出“蓝色轮廓”，维里参数小于 2，表明在这些巨大的团块中正在发生全球坍塌。CO(4-3) 线通过两层模型拟合，以获得下落速度和质量下落率。推导的质量下降率范围为 10 ^-3至 10 ^-1 M _⊙ yr ^-1. 团块质量和下落率之间的正相关关系似乎表明重力在塌陷过程中起主导作用。较高光度的团块具有较大的质量下降率，这意味着具有较高质量下降率的团块具有较高的恒星形成率。