Related papers: Are galactic coronae thermally unstable?
Substantial numbers of morphologically regular early-type (elliptical and lenticular) galaxies contain molecular gas, and the quantities of gas are probably sufficient to explain recent estimates of the current level of star formation…
Galactic halos accrete material from the intergalactic medium (IGM) and part of this accretion is expected to be in the form of cool ($T\sim10^4$ K) gas. A signature of this process could reside in the detection of numerous clouds in the…
We investigate the properties of halo gas using three cosmological `zoom-in' simulations of realistic Milky Way-galaxy analogs with varying sub-grid physics. In all three cases, the mass of hot ($T > 10^6$ K) halo gas is $\sim 1\%$ of the…
A few results that indicate the presence of temperature variations in gaseous nebulae are reviewed. The evidence is based on: a) temperatures derived from different methods, and b) on comparisons of abundances predicted by models of…
The influence of rotation and magnetic fields on the physical properties of isothermal gas clouds is discussed. The presence of rotation and/or magnetic fields results in an increase of the critical cloud mass with respect to gravitational…
We have investigated steady, radial gas outflows (or winds) from galaxies and the development of thermal instability in the hot gas. In order to see the maximum influence of the instability on the global structure of the galactic outflows,…
Galactic spiral shocks are dominant morphological features and believed to be responsible for substructure formation within spiral arms in disk galaxies. They can also contribute a substantial amount of kinetic energy to the interstellar…
The Milky Way's bar dominates the orbits of stars and the flow of cold gas in the inner Galaxy, and is therefore of major importance for Milky Way dynamical studies in the Gaia era. Here we discuss the pronounced peanut shape of the…
Stars form from cold molecular interstellar gas. Since this is relatively rare in the local Universe, galaxies like the Milky Way form only a few new stars per year. Typical massive galaxies in the distant Universe formed stars an order of…
The circumgalactic region of the Milky Way contains a large amount of gaseous mass in the warm-hot phase. The presence of this warm-hot halo observed through $z=0$ X-ray absorption lines is generally agreed upon, but its density,…
Molecular clouds are a fundamental ingredient of galaxies: they are the channels that transform the diffuse gas into stars. The detailed process of how they do it is not completely understood. We review the current knowledge of molecular…
Recently X-ray observations have shown the common presence of compact galactic coronae around intermediate-mass spheroid galaxies embedded in the intracluster/intragroup medium (ICM). We conduct 2-D hydrodynamic simulations to study the…
Molecular gas disks are generally Toomre stable ($Q_T>$1) and yet clearly gravitationally unstable to structure formation as evidenced by the existence of molecular clouds and ongoing star formation. This paper adopts a 3D perspective to…
The inner few hundred parsecs of the Milky Way harbours gas densities, pressures, velocity dispersions, an interstellar radiation field and a cosmic ray ionisation rate orders of magnitude higher than the disc; akin to the environment found…
Optically thin cooling gas at most temperatures above 30K will make condensations by pressure pushing material into cool dense regions. This works without gravity. Cooling condensations will flatten and become planar/similarity solutions.…
We characterize empirically the radial diffusion of stars in the plane of a typical barred disk galaxy by calculating the local spatial diffusion coefficient and diffusion time-scale for bulge-disk-halo N-body self-consistent systems which…
We run self-consistent simulations of Milky Way-sized, isolated disk galaxies to study formation and evolution of a stellar bar as well as a nuclear ring in the presence of gas. We consider two sets of models with cold or warm disks that…
Disk galaxies evolve over time through processes that may rearrange both the radial mass profile and the metallicity distribution within the disk. This review of such slow changes is largely, though not entirely, restricted to…
Galaxies are missing most of their baryons, and many models predict these baryons lie in a hot halo around galaxies. We establish observationally motivated constraints on the mass and radii of these haloes using a variety of independent…
Using H I absorption spectra taken from the recent surveys of 21-cm line and continuum emission in the Galactic plane, the distribution of cool atomic clouds in the outer disk of the Milky Way is revealed. The warp of the midplane is…