SIMBAD references

The research of infall motion is a common means to study molecular cloud dynamics and the early process of star formation. Many works had been done in-depth research on infall. We searched the literature related to infall study of molecular cloud since 1994, summarized the infall sources identified by the authors. A total of 456 infall sources are cataloged. We classify them into high-mass and low-mass sources, in which the high-mass sources are divided into three evolutionary stages: prestellar, protostellar and H II region. We divide the sources into clumps and cores according to their sizes. The H₂ column density values range from 1.21 × 10²¹ to 9.75 × 10²⁴ cm^–2, with a median value of 4.17 × 10²² cm^–2. The H₂ column densities of high-mass and low-mass sources are significantly separated. The median value of infall velocity for high-mass clumps is 1.12 km s^–1, and the infall velocities of low-mass cores are virtually all less than 0.5 km s^–1. There is no obvious difference between different stages of evolution. The mass infall rates of low-mass cores are between 10^–7 and 10^–4M_⊙yr^–1, and those of high-mass clumps are between 10^–4 and 10^–1M_⊙yr^–1 with only one exception. We do not find that the mass infall rates vary with evolutionary stages.