A Survey for Infall Motions toward Starless Cores. II. CS (2–1) and N 2 H + (1–0) Mapping Observations
نویسندگان
چکیده
منابع مشابه
On the internal structure of starless cores . I . Physical conditions and the distribution of CO , CS , N 2 H + , and NH 3 in L 1498 and L 1517
We have characterized the physical structure and chemical composition of two close-to-round starless cores in Taurus-Auriga, L1498 and L1517B. Our analysis is based on high angular resolution observations in at least two transitions of NH3, N2H + , CS, C 34 S, C 18 O, and C 17 O, together with maps of the 1.2 mm continuum. For both cores, we derive radial profiles of constant temperature and co...
متن کاملRadiative Transfer and Starless Cores
We develop a method of analyzing radio frequency spectral line observations to derive data on the temperature, density, velocity, and molecular abundance of the emitting gas. The method incorporates a radiative transfer code with a new technique for handling overlapping hyperfine emission lines within the accelerated lambda iteration algorithm and a heuristic search algorithm based on simulated...
متن کاملHigh - Mass Starless Cores
We report the identification of a sample of potential High-Mass Starless Cores (HMSCs). The cores were discovered by comparing images of the fields containing candidate High-Mass Protostellar Objects (HMPOs) at 1.2mm and mid-infrared (8.3µm; MIR) wavelengths. While the HMPOs are detected at both wavelengths, several cores emitting at 1.2mm in the same fields show absorption or no emission at th...
متن کاملOscillations of starless cores
If the split, asymmetric molecular spectral line profiles that are seen in many starless cores are interpreted as indicative of global collapse or expansion of the core then one possible implication is that most starless cores have short lifetimes on the order of the collapse or sound crossing time scale. An alternative interpretation of the line profiles as indicative of perturbations on an un...
متن کاملUsing Chemistry to Unveil the Kinematics of Starless Cores : Complex Radial Motions in Barnard 68
We present observations of CO, CO, HCO, HCO, DCO and N2H + line emission towards the Barnard 68 starless core. The line profiles are interpreted using a chemical network coupled with a radiative transfer code in order to reconstruct the radial velocity profile of the core. Our observations and modeling indicate the presence of complex radial motions, with the inward motions in the outer layers ...
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ژورنال
عنوان ژورنال: The Astrophysical Journal Supplement Series
سال: 2001
ISSN: 0067-0049,1538-4365
DOI: 10.1086/322534