Related papers: Spectroscopic Evidence for Gas Infall in GF9-2

We present a study of the natal core harboring the class 0 protostar GF9-2 in the filamentary dark cloud GF 9 (d = 200 pc). GF9-2 stands unique in the sense that it shows H2O maser emission, a clear signpost of protostar formation, whereas…

To study physical properties of the natal filament gas around the cloud core harboring an exceptionally young low-mass protostar GF9-2, we carried out J=1-0 line observations of 12CO, 13CO, and C18O molecules using the Nobeyama 45m…

Previous observations have revealed an accretion disk and outflow motion in high-mass star-forming region G192.16-3.84. While collapse have not been reported before. We present here molecular line and continuum observations toward massive…

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 carried out an unbiased mapping survey of dense molecular cloud cores traced by the NH3 (1,1) and (2,2) inversion lines in the GF9 filament which contains an extremely young low-mass protostar GF9-2 (Furuya et al. 2006, ApJ, 653, 1369).…

Gas accretion is a key process in star formation. However, the gas infall detections in high-mass star forming regions with high-spatial resolution observations are rare. Here we report the detection of gas infall towards a cometary…

We present CS(3-2) and DCO+(2-1) observations of 94 starless cores and compare the results with previous CS(2-1) and N2H+(1-0) observations to study inward motions in starless cores. The velocity shifts of the CS(3-2) and (2-1) lines with…

We have used the IRAM 30-m telescope to map some targets with HCO$^+$ (1-0) and H$^{13}$CO$^+$ (1-0) lines in order to search for gas infall evidence in the clumps. In this paper, we report the mapping results for 13 targets. All of these…

Gravitational accretion accumulates the original mass, and this process is crucial for us to understand the initial phases of star formation. Using the specific infall profiles in optically thick and thin lines, we searched the clumps with…

We present a multi-wavelength observational study towards the high-mass young stellar object G8.68-0.37. A single massive gas-and-dust core is observed in the (sub)millimeter continuum and molecular line emissions. We fitted the spectral…

The results are presented of a molecular line survey to search for the spectral signature of infall towards 77 850 micron continuum sources believed to be candidate high mass protostellar objects. Up to six different transitions, HCO+ 1-0,…

We present the results of a single dish survey toward 95 VeLLOs in optically thick (HCN 1-0) and thin ($\rm N_2H^+$ 1-0) lines performed for the purpose of understanding the physical processes of inward motions in the envelopes of the…

Although surveys of infall motions in dense cores have been carried out for years, few surveys have focused on mapping infall across cores using multiple spectral line observations. To fill this gap, we present IRAM 30-m Telescope maps of…

We present observations of the v2=0 and vibrationally excited v2=1 J=9-8 rotational lines of HCN at 797 GHz toward the deeply embedded massive young stellar object GL 2591, which provide the missing link between the extended envelope traced…

We revisit the interpretation of blue-excess molecular lines from dense collapsing cores, considering recent numerical results that suggest prestellar core collapse occurs from the outside-in, and not inside-out. We thus create synthetic…

We present the results of a high resolution study with the Submillimeter Array towards the massive star forming complex G9.62+0.19. Three sub-mm cores are detected in this region. The masses are 13, 30 and 165 M$_{\sun}$ for the northern,…

We present a survey toward 16 Low Luminosity Objects (LLOs with an internal luminosity, Lint, lower than 0.2 Lsun) with N2H+ (1-0), N2H+ (3-2), N2D+ (3-2), HCO+ (3-2) and HCN (3-2) using the Arizona Radio Observatory Kitt Peak 12m Telescope…

HH 212 is a highly collimated jet discovered in H2 powered by a young Class 0 source, IRAS 05413-0104, in the L1630 cloud of Orion. We have mapped around it in 1.33 mm continuum, 12CO ($J=2-1$), 13CO ($J=2-1$), C18O ($J=2-1$), and SO ($J_K…

We report high angular resolution observations, made with the Atacama Large Millimeter Array in band 6, of high excitation molecular lines of $\rm CH_3CN$ and $\rm SO_2$ and of the H29$\alpha$ radio recombination line towards the…

We present observations of CO, 13CO and of H2O in the middle and far-infrared taken with the ISO-SWS and ISO-LWS spectrometers toward two positions in the Galactic Center region (Sgr A* and GCS-3). Both ice and gas phase molecules are…