Related papers: From diffuse gas to dense molecular cloud cores
Our current understanding of the physical processes of star formation is reviewed, with emphasis on processes occurring in molecular clouds like those observed nearby. The dense cores of these clouds are predicted to undergo gravitational…
At a distance of 8 kpc only, the center of the Galaxy provides a unique testbed for studies about the physics of the interstellar medium and star formation in the nuclei of galaxies. Since it shares many properties of other, more…
The angular momentum of molecular cloud cores plays an essential role in the star formation process. However, the time evolution of the angular momentum of molecular cloud cores is still unclear. In this paper, we perform three-dimensional…
The interstellar medium (ISM) can be thought of as the galactic atmosphere which fills the space between stars. When clouds within the ISM collapse, stars are born. When the stars die, they return their matter to the surrounding gas.…
We develop a theory for filamentary molecular clouds including the effects of ordered magnetic fields, and external pressure. We first derive a form of the virial equation appropriate for filamentary clouds. By comparing with observational…
We discuss the connection between the chemistry of dense interstellar clouds and those characteristics of cometary matter that could be remnants of it. The chemical evolution observed to occur in molecular clouds is summarized and a model…
The main achievements, current developments and prospects of molecular studies in external galaxies are reviewed. They are put in the context of the results of several decades of studies of molecules in local interstellar medium, their…
We present a catalogue of molecular cloud cores drawn from high latitude, medium opacity clouds, using the all-sky IRAS Sky Survey Atlas (ISSA) images at 60 and 100~$\mu$m. The typical column densities of the cores are $ N(H_2)\sim 3.8…
Magnetic fields are dynamically important in the diffuse interstellar medium. Understanding how gravitationally bound, star-forming clouds form requires modeling of the fields in a self-consistent, supernova-driven, turbulent, magnetized,…
We investigate the star-formation in cometary tails of galaxies in clusters. In particular, we focus on the evolution of molecular clouds in the tails that generate the stars. Assuming that the gas tails had been derived from the galaxies…
We review the main results from recent numerical simulations of turbulent fragmentation and star formation. Specifically, we discuss the observed scaling relationships, the ``quiescent'' (subsonic) nature of many star-forming cores, their…
Stars form from dense cores in turbulent molecular clouds. According to the standard scenario of star formation, dense cores are created by cloud fragmentation. However, the physical mechanisms driving this process are still not fully…
The formation of massive stellar clusters in turbulent molecular clouds is investigated. We include artificial star formation and energy feedback of newly born stars. The obtained systems are not likely to survive. Case studies to determine…
(Abridged) The building blocks of galaxies are star clusters. These form with low-star formation efficiencies and, consequently, loose a large part of their stars that expand outwards once the residual gas is expelled by the action of the…
A fraction of the dense cores within a turbulent molecular cloud will eventually collapse to form stars. Identifying the physical criteria for instability and analyzing critical core properties is therefore necessary to star formation…
Large-scale surveys of the Perseus molecular cloud have provided many clues as to the processes occurring during star formation. Here, analysis of both column density maps and kinematic data (maps and pointed data) are discussed and…
Turbulent fragmentation determines where and when protostellar cores form, and how they contract and grow in mass from the surrounding cloud material. This process is investigated, using numerical models of self-gravitating molecular cloud…
We used CO (2-1) and CO (1-0) data cubes to identify molecular clouds and study their kinematics and dynamics in three nearby galaxies and the inner Milky Way. When observed at similar spatial and velocity resolutions, molecular clouds in…
Star formation takes place in filamentary molecular clouds which arise by physical processes that take place in the cold, neutral medium (CNM). We address the necessary conditions for this diffuse ($n \approx 30$ cm$^{-3}$), cold (T…
Much of what we know about molecular clouds, and by extension star formation, comes from molecular line observations. Interpreting these correctly requires knowledge of the underlying molecular abundances. Simulations of molecular clouds…