相关论文: L1521E: the first starless core with no molecular …

The CNO cycle is the main source of energy in stars more massive than our Sun. It defines the energy production and the duration contributes in determining the lifetime of massive stars. The cycle is an important tool for the determination…

We study the evidence for a diversity of formation processes in early-type galaxies by presenting the first complete volume-limited sample of slow rotators with both integral-field kinematics from the ATLAS3D Project and high spatial…

Complex organic molecules (COMs) in starless cores provide critical insights into the early stages of star formation and prebiotic chemistry. We present a chemical survey of 16 starless cores (including five prestellar cores) in the Orion A…

We present C18O observations of the pre-stellar core L1689B, in the (J=3-2) and (J=2-1) rotational transitions, taken at the James Clerk Maxwell Telescope in Hawaii. We use a lambda-iteration radiative transfer code to model the data. We…

Lynds 1340, a molecular cloud forming intermediate-mass stars, has been mapped in the NH_3(1,1) and (2,2) transitions with the Effelsberg 100m telescope. We observed the whole area of the cloud where C18O emission was detected earlier, at a…

We have observed several emission lines of two Nitrogen-bearing (C2H5CN and C2H3CN) and two Oxygen-bearing (CH3OCH3 and HCOOCH3) molecules towards a sample of well-known hot molecular cores (HMCs) in order to check whether the chemical…

We explore possible depletion factors for Li6 in the three stars where it has been detected. To this end, we assume that 6Li/H scales as 16O/H throughout the galactic evolution, an assumption motivated by the observations of a similar…

Partially depleted cores, as measured by core-Sersic model "break radii", are typically tens to a few hundred parsecs in size. Here we investigate the unusually large (cusp radius of 4.57 kpc) depleted core recently reported for Holm 15A,…

Dust grains play a key role in the physics of star-forming regions, even though they constitute only $\sim$1 % of the mass of the interstellar medium. The derivation of accurate dust parameters such as temperature ($T_{dust}$), emissivity…

Models of self-gravitating gas in the early stages of pressure-free collapse are compared for initial states which are equilibrium layers, cylinders, and Bonnor-Ebert spheres. For each geometrical case the density profile has an inner…

We investigated the chemistry of nitrogen--containing species, principally isotopomers of CN, HCN, and HNC, in a sample of pre-protostellar cores. We used the IRAM 30 m telescope to measure the emission in rotational and hyperfine…

We present a high spectral resolution survey of the most metal-poor damped Lyman-alpha absorption systems (DLAs) aimed at probing the nature and nucleosynthesis of the earliest generations of stars. Our survey comprises 22 systems with iron…

We present SWAS observations of water vapor in two cold star-less clouds, B68 and Core D in rho Ophiuchus. Sensitive non-detections of the 1(10)-1(01) transition of o-H2O are reported for each source. Both molecular cores have been…

We derive abundances and central star parameters for 15 planetary nebulae (PNe) in M31: 12 in the bulge and 3 in a disk field 14 kpc from the nucleus. No single abundance value characterizes the bulge stars: although the median abundances…

Evidence for a large scale flow of low density gas onto the Cepheus A young stellar cluster is presented. Observations of K-band near-infrared and multi-transition CS and N2H+ millimeter line emission are shown in relation to a…

We have retrieved Spitzer archive data of pre-stellar cores taken with the Multiband Imaging Photometer for Spitzer (MIPS) at a wavelength of 160 um. Seventeen images, containing eighteen cores, were constructed. Flux densities were…

We have carried out observations of the starless core L1544 in the CCS (J_N=3_2-2_1) line at 9 millimeters wavelength using the BIMA array. The maps show an elongated condensation, 0.15 x 0.045 pc in size, with stronger emission at the…

Infrared-dark high-mass clumps are among the most promising objects to study the initial conditions of the formation process of high-mass stars and rich stellar clusters. In this work, we have observed the (3-2) rotational transition of…

We carry out an ALMA $\rm N_2D^+$(3-2) and 1.3~mm continuum survey towards 32 high mass surface density regions in seven Infrared Dark Clouds with the aim of finding massive starless cores, which may be the initial conditions for the…

Molecular inventories in starless cores are powerful tools for probing the physical and chemical structures at the earliest stages of star formation. Wide-band spectral scans are invaluable for obtaining a comprehensive view of the chemical…