Related papers: Why most molecular clouds are gravitationally domi…
We simulate the formation of molecular clouds in colliding flows of warm neutral medium with the adaptive mesh refinement code {\sc Flash}. We include a chemical network to treat heating and cooling and to follow the formation of molecular…
Molecular cloud observations show that clouds have non-thermal velocity dispersions that scale with the cloud size as $\sigma\propto R^{1/2}$ at constant surface density, and for varying surface density scale with both the cloud`s size and…
We perform numerical simulations of nonlinear MHD waves in a gravitationally stratified molecular cloud that is bounded by a hot and tenuous external medium. We study the relation between the strength of the turbulence and various global…
Gravity drives the collapse of molecular clouds through which stars form, yet the exact role of gravity in cloud collapse remains a complex issue. Studies point to a picture where star formation occurs in clusters. In a typical, pc-sized…
We compute the star formation rate (SFR) in molecular clouds (MCs) that originate {\it ab initio} in a new, higher-resolution simulation of supernova-driven turbulence. Because of the large number of well-resolved clouds with…
The rotation of the galactic objects has been seen by asymmetric Doppler shift in the CMB data. Molecular hydrogen clouds at virial temperature may contribute to the galactic halo dark matter and they might be the reason for the observed…
All stars are born in molecular clouds, and most in giant molecular clouds (GMCs), which thus set the star formation activity of galaxies. We first review their observed properties, including measures of mass surface density, Sigma, and…
We examine the idea that diffuse and giant molecular clouds and their substructure form as density fluctuations induced by large scale interstellar turbulence. We do this by investigating the topology of various fields in realistic…
In a series of papers we investigate the effect of collisions between turbulent molecular clouds on their structure, evolution and star formation activity. In this paper we look into the role of the clouds' initial virial ratios. Three…
Molecular clouds (MC) are the densest and coldest component of the interstellar gas, and the sites of star formation. They are also turbulent and fractal and their masses and sizes span several orders of magnitude. It is also generally…
The grand-design spiral galaxy M~51 was observed at 40pc resolution in CO(1--0) by the PAWS project. A large number of molecular clouds were identified and we search for velocity gradients in two high signal-to-noise subsamples, containing…
The gravitational binding and star-forming properties of molecular clouds (MCs) in the Milky Way (MW) are estimated from CO cloud observations and from a model of pressure-bounded virial equilibrium (PVE). Two CO surveys are analyzed with…
How does turbulence contribute to the formation and structure of the dense interstellar medium (ISM)? Molecular clouds are dense, high-pressure objects. It is usually argued that gravitational confinement causes the high pressures, and that…
Gravity plays a determining role in the evolution of the molecular ISM. In \citet{2016arXiv160304342L}, we proposed a measure called gravitational energy spectrum to quantify the importance of gravity on multiple physical scales. In this…
To investigate how molecular clouds react to different environmental conditions at a galactic scale, we present a catalogue of giant molecular clouds resolved down to masses of $\sim 10$~M$_{\odot}$ from a simulation of the entire disc of…
We discuss the virial balance of all members of a cloud ensemble in numerical simulations of self-gravitating MHD turbulence. We first discuss the choice of reference frame for evaluating the terms entering the virial theorem (VT),…
Turbulence governs the fragmentation of molecular clouds and plays a pivotal role in star formation. The persistence of observed cloud turbulence suggests it does not decay significantly within the turnover timescale, implying a recurrent…
CMZoom survey observations with the Submillimeter Array are analyzed to describe the virial equilibrium (VE) and star-forming potential of 755 clumps in 22 clouds in the Central Molecular Zone (CMZ) of the Milky Way. In each cloud, nearly…
We analyse extinction maps of nearby Giant Molecular Clouds to forge a link between driving processes of turbulence and modes of star formation. Our investigation focuses on cloud structure in the column density range above the self…
We review the properties of turbulent molecular clouds (MCs), focusing on the physical processes that influence star formation (SF). MC formation appears to occur during large-scale compression of the diffuse ISM driven by supernovae,…