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 catalogued. 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 HII region. We divide the sources into clumps and cores according to their sizes. The H$_2$ column density values range from 1.21$\times$ 10$^{ 21}$ to 9.75 $\times$ 10$^{ 24}$ cm$^{ -2}$, with a median value of 4.17$\times$ 10$^{ 22}$ cm$^{ -2}$. The H$_2$ 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$^{ -4}$ M$_{ \odot} \text{ yr}^{ -1}$, and those of high-mass clumps are between 10$^{ -4}$ and 10$^{ -1}$ M$_{ \odot} \text{ yr}^{ -1}$ with only one exception. We do not find that the mass infall rates vary with evolutionary stages.
Categories: astro-ph.GA