A Catalog of Molecular Clumps and Cores with Infall Signatures

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 H-2 column density values range from 1.21 x 10(21) to 9.75 x 10(24) cm(-2), with a median value of 4.17 x 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 (circle dot)yr(-1), and those of high-mass clumps are between 10(-4) and 10(-1) M (circle dot)yr(-1) with only one exception. We do not find that the mass infall rates vary with evolutionary stages.

Automated summary

The research of infall motion is a common means to study molecular cloud dynamics and the early process of star formation. Many works have been done on infall, and this study catalogs 456 infall sources and classifies them into clumps and cores based on their sizes.