Related papers: Molecular Line Profile Fitting with Analytic Radia…
Context. This study is part of a large project to study the physics of accretion and molecular outflows towards a selected sample of high-mass star-forming regions that show evidence of infall and rotation from previous studies. Aims. We…
We describe a model for the thermal and dynamical equilibrium of starless cores that includes the radiative transfer of the gas and dust and simple CO chemistry. The model shows that the structure and behavior of the cores is significantly…
Chemical composition of the massive cores forming high-mass stars can put some constrains on the time scale of the massive star formation: sulphur chemistry is of specific interest due to its rapid evolution in warm gas and because the…
We study chromospheric emission to understand the temperature stratification in the solar chromosphere. We observed the intensity profile of the CaIIH line in a quiet Sun region close to the disk center at the German Vacuum Tower Telescope.…
We report the results of an HCO+ (3-2) and N2D+ (3-2) molecular line survey performed toward 91 dense cores in the Perseus molecular cloud using the James Clerk Maxwell Telescope, to identify the fraction of starless and protostellar cores…
The cosmic-ray ionization rate ($\zeta_2$) is one of the key parameters in star formation, since it regulates the chemical and dynamical evolution of molecular clouds by ionizing molecules and determining the coupling between the magnetic…
We present the results of a mid-infrared (7 micron) imaging survey of a sample of 24 starless dense cores carried out at an angular resolution of 6 arcsec with the ISOCAM camera aboard the Infrared Space Observatory (ISO). The targeted…
The carbon monoxide (CO) rotational transition lines are the most common tracers of molecular gas within giant molecular clouds (MCs). We study the ratio ($R_{2-1/1-0}$) between CO's first two emission lines and examine what information it…
Molecular line observations of starless (prestellar) cores combined with a chemical evolution modeling and radiative transfer calculations are a powerful tool to study the earliest stages of star formation. However, conclusions drawn from…
We study the anisotropy of centroid and integrated intensity maps with synthetic observations. We perform post-process radiative transfer including the optically thick regime that was not covered in Hern\'andez-Padilla et al. (2020). We…
In an attempt to understand the dynamics of collapsing starless cores, we have onducted a detailed investigation of the velocity fields of two collapsing cores, L694-2 and L1197, with high spatial resolution HCN J=1-0 maps and Monte Carlo…
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 surveyed 81 dense molecular cores associated with regions of massive star formation and Sgr A in the 5_{05}-4_{04} and 10_{010}-9_{09} lines of HNCO. Line emission was detected towards 57 objects. Selected subsamples were also observed…
(Abridged) We present evidence that low-mass starless cores, the simplest units of star formation, are systematically differentiated in their chemical composition. Molecules including CO and CS almost vanish near the core centers, where the…
Two selected regions in the molecular gas spiral arms in M51 were mapped with the Owens Valley Radio Observatory (OVRO) mm-interferometer in the 12CO(2-1), 13CO(1-0), C18O(1-0), HCN(1-0) and HCO+(1-0) emission lines. The CO data have been…
We quantify if the chemical abundance gradients given by a dynamical model of core collapse including time-dependent changes in density and temperature differ greatly from abundances derived from static models, where the density and…
In this study, 36 cores (30 starless and 6 protostellar) identified in Orion were surveyed to search for inward motions. We used the Nobeyama 45 m radio telescope, and mapped the cores in the $J = 1\rightarrow0$ transitions of HCO$^+$,…
We present a new analytical three-parameter formula to fit observed column density profiles of prestellar cores. It represents a line-of-sight integral through a spherically symmetric or disc-like isothermal cloud. The underlying model…
Aims: We investigate a new method to for obtaining the plasma parameters of solar prominences observed in the Mgii h&k spectral lines by comparing line profiles from the IRIS satellite to a bank of profiles computed with a one-dimensional…
We investigate differences in the molecular abundances between magnetically super- and sub-critical prestellar cores, performing three-dimensional non-ideal magnetohydrodynamical (MHD) simulations with varying densities and magnetic field…