相关论文: Molecular Line Profiles of Collapsing Gas Clouds
Using recent dust continuum data, we generate the intrinsic ellipticity distribution of dense, starless molecular cloud cores. Under the hypothesis that the cores are all either oblate or prolate randomly-oriented spheroids, we show that a…
Molecular hydrogen being unobservable in cold molecular clouds, the column density measurements of molecular gas currently rely either on dust emission observation in the far-IR or on star counting. (Sub-)millimeter observations of numerous…
We present the results of a high angular resolution, multi-transition analysis of the molecular gas in M82. The analysis is based on the two lowest transitions of 12CO and the ground transition of the rare isotopes 13CO and C18O measured…
We develop analytic approximations to the density evolution of prestellar cores, based on the results of hydrodynamical simulations. We use these approximations as input for a time-dependent gas-grain chemical code to investigate the…
We present calculations of molecular, atomic and ionic line emission from simulations of giant molecular cloud (GMC) collisions. We post-process snapshots of the magneto-hydrodynamical simulations presented in an earlier paper in this…
In this study, the main goal is to understand the molecular cloud core collapse through the stages of first and second hydrostatic core formation. We investigate the properties of Larson's first and second cores following the evolution of…
We study the formation, evolution and collapse of dense cores by tracking structures in a magnetohydrodynamic simulation of a star-forming cloud. We identify cores using the dendrogram algorithm and utilize machine learning techniques,…
We summarize the current status of the turbulent model of star formation in turbulent molecular clouds. In this model, clouds, clumps and cores form a hierarchy of nested density fluctuations caused by the turbulence, and either collapse or…
We review recent advances in the analytical and numerical modeling of the star formation rate in molecular clouds and discuss the available observational constraints. We focus on molecular clouds as the fundamental star formation sites,…
Complex organic molecules (COMs), the building blocks of life, have been extensively detected under various physical conditions, from quiescent clouds to star-forming regions. They therefore serve as excellent tracers for the local physical…
The advent of new sub-millimeter observational facilities has stimulated the desire to model the sub-mm line emission of galaxies within cosmological galaxy formation models. This is typically done in post-processing by applying…
During the gravitational core collapse of a massive progenitor star which may give rise to at least a class of gamma-ray bursts (GRBs) associated with supernovae, a stellar core rapidly passes through a short yet important phase of…
Context: Atomic and molecular cloud formation is a dynamical process. However, kinematic signatures of these processes are still observationally poorly constrained. Methods: Targeting the cloud-scale environment of the prototypical infrared…
Most of our knowledge regarding molecular clouds and the early stages of star formation stems from molecular spectral-line observations. However, the various chemical and radiative-transfer effects, in combination with projection effects,…
A reliable estimate of the molecular gas content in galaxies plays a crucial role in determining their dynamical and star-forming properties. However, H2, the dominant molecular species, is difficult to observe directly, particularly in the…
In this paper we discuss two approximate methods previously suggested for modeling hyperfine spectral line emission for molecules whose collisional transitions rates between hyperfine levels are unknown. Hyperfine structure is seen in the…
We present Green Bank Telescope (GBT) observations of the 3(12)-3(13) (29 GHz) and 4(13)-4(14) (48 GHz) transitions of the H2CO molecule toward a sample of 23 well-studied star-forming regions. Analysis of the relative intensities of these…
The formation of stars is inextricably linked to the structure of their parental molecular clouds. Here we take a number of nearby giant molecular clouds (GMCs) and analyse their column density and mass distributions. This investigation is…
We examine the conditions under which binary and multiple stars may form out of turbulent molecular cloud cores using high resolution 3-D, adaptive mesh refinement (AMR) hydrodynamics (Truelove et al., 1997, 1998; Klein, 1999). We argue…
Using arguments parallel to those used in support of using H2CO as a sensitive probe of temperature and density in molecular clouds, we measured the J=7-6 and J=10-9 transitions of thioformaldehyde (H2CS) in several hot core sources. The…