Related papers: Does Infall End Before the Class I Stage?

We have carried out a survey toward the central regions of 85 starless cores in HCN J = 1-0 to study inward motions in the cores. Sixty-four cores were detected with HCN lines. The infall asymmetry in the HCN spectra is found to be more…

We have carried out radiative transfer calculations of infalling, dusty envelopes surrounding embedded protostars to understand the observed properties of the recently identified ``Class 0'' sources. To match the far-infrared peaks in the…

We present a study of analytic models of starless cores whose line profiles have ``infall asymmetry,'' or blue-skewed shapes indicative of contracting motions. We compare the ability of two types of analytical radiative transfer models to…

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…

We present the detection of kinematic infall signatures towards the Class 0 protostellar system SMM4 in the Serpens cloud core. We have observed the dense molecular gas towards the embedded source using millimeter and submillimeter line…

Gas infall motions play a crucial role in high-mass star formation and are characterized by observable signatures in the form of blue-shifted asymmetric spectral line profiles ("blue profiles"). However, the connection between blue profiles…

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…

Observations of atomic or molecular lines can provide important information about the physical state of star forming regions. In order to investigate the line profiles from dynamical collapsing massive star forming regions (MSFRs), we model…

(Context) Many physical parameters change with time in star forming regions. Here we attempt to correlate changes in infall and outflow motions in high mass star forming regions with evolutionary stage using JCMT observations. (Aims) From a…

The evolutionary sequence for high-mass star formation starts with massive starless clumps that go on to form protostellar, young stellar objects and then compact HII regions. While there are many examples of the three later stages, the…

The onset of massive star formation is not well understood because of observational and theoretical difficulties. To find the dense and cold clumps where massive star formation can take place, we compiled a sample of high infrared…

Observational evidence for inflowing motions in massive star forming regions has been extremely rare. We have made a spectroscopic survey of a sample of 28 massive star forming cores associated with water masers. An optically thick line of…

We present the results of an extensive mapping survey of 53 `starless' cores in the optically thick line of CS 2-1 and the optically thin lines of N2H+ 1-0 and C18O 1-0. The purpose of this survey was to search for signatures of extended…

Using molecular line data from the Millimetre Astronomy Legacy Team 90 GHz Survey (MALT90), we have searched the optically thick \hcop\, line for the "blue asymmetry" spectroscopic signature of infall motion in a large sample of high-mass,…

Recent observational and theoretical investigations have emphasised the importance of filamentary networks within molecular clouds as sites of star formation. Since such environments are more complex than those of isolated cores, it is…

We present maps of seven sources selected from Klaassen & Wilson (2007a) in SiO (J=8-7) and HCO$^+$ and H$^{13}$CO$^+$ (J=4-3) which were obtained using HARP-B on the James Clerk Maxwell Telescope. We find that four out of our seven sources…

With the GREAT receiver at the Stratospheric Observatory for Infrared Astronomy (SOFIA), nine massive molecular clumps have been observed in the ammonia $3_{2+}- 2_{2-}$ line at 1.8~THz in a search for signatures of infall. The sources were…

Using archive data from the Millimeter Astronomy Legacy Team Survey at 90 GHz (MALT90), carried out using the Mopra 22-m telescope, we made the first multi-transition molecular line study of infrared dark cloud (IRDC) MSXDC G331.71+00.59.…

We have observed 37 Infrared Dark Clouds (IRDCs), containing a total of 159 clumps, in high-density molecular tracers at 3 mm using the 22-meter ATNF Mopra Telescope located in Australia. After determining kinematic distances, we eliminated…

The infall of material onto a protostar, in the case of optically thick line emission, produces an asymmetry in the blue- and red-wing line emission. For an angularly resolved emission, this translates in a blue central spot in the…