In search for infalling clumps in molecular clouds -- A catalogue of CO blue-profiles

Abstract

We have started a systematic survey of molecular clumps with infall motions to study the very early phase of star formation. Our first step is to utilize the data products by MWISP to make an unbiased survey for blue asymmetric line profiles of CO isotopical molecules. Within a total area of $\sim$ 2400 square degrees nearby the Galactic plane, we have found 3533 candidates showing blue-profiles, in which 3329 are selected from the ${}^{12}$CO&${}^{13}$CO pair and 204 are from the ${}^{13}$CO&C${}^{18}$O pair. Exploration of the parametric spaces suggests our samples are in the cold phase with relatively high column densities ready for star formation. Analysis of the spatial distribution of our samples suggests that they exist virtually in all major components of the Galaxy. The vertical distribution suggest that the sources are located mainly in the thick disk of $\sim$ 85 parsec, but still a small part are located far beyond Galactic midplane. Our follow-up observation indicates that these candidates are a good sample to start a search for infall motions, and to study the condition of very early phase of star formation.

References in corpus (16)

• Trigonometric Parallaxes Of High-Mass Star Forming Regions: Our View Of The Milky Way
• A Minimum Column Density of 1 g cm^-2 for Massive Star Formation
• CO Isotopologues in the Perseus Molecular Cloud Complex: the X-Factor and Regional Variations
• The Milky Way Imaging Scroll Painting (MWISP): Project Details and Initial Results from the Galactic Longitude of 25.8deg to 49.7deg
• Unfolding the Laws of Star Formation: The Density Distribution of Molecular Clouds
• High-mass Star Formation through Filamentary Collapse and Clump-fed Accretion in G22
• Signatures of inflow motion in cores of massive star formation: Potential collapse candidates
• Infall Motions in Massive Star-Forming Regions: Results from Years 1 & 2 of the MALT90 Survey
• A multi-transition molecular line study of inward motions towards massive star-forming cores
• Molecular gas distribution perpendicular to the Galactic plane
• Molecular Clouds in the Second Quadrant of the Milky Way Mid-plane from l$=$104$.{}^{\circ }$75 to l=119$.{}^{\circ }$75 and b=$-$5$.{}^{\circ }$25 to b=5$.{}^{\circ }$25
• The inflow signature toward different evolutionary phases of massive star formation
• In Search for Infall Motion in molecular clumps II: HCO+ (1-0) and HCN (1-0) Observations toward a Sub-sample of Infall Candidates
• Gas infalling motions in the envelopes of Very Low Luminosity Objects
• A Catalog of Molecular Clumps and Cores with Infall Signatures
• Study of the 13CO/C18O abundance ratio towards the filamentary infrared dark cloud IRDC 34.43+0.24