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 have "blue profile" in 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 by the two-layer model in order to obtain infall velocities and mass infall rates. Derived mass infall rates are 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 clump has larger mass infall rate, implying that the clump with higher mass infall rate has higher star formation rate.
@article{arxiv.2010.10731,
title = {Infall in massive clumps harboring bright infrared sources},
author = {Ying-Hua Yue and Sheng-Li Qin and Tie Liu and Meng-Yao Tang and Yuefang Wu and Ke Wang and Chao Zhang},
journal= {arXiv preprint arXiv:2010.10731},
year = {2021}
}