Related papers: Does External Pressure Explain Recent Results for …
Measurements by dust detectors on interplanetary spacecraft appear to indicate a substantial flux of interstellar particles with masses exceeding 10^{-12}gram. The reported abundance of these massive grains cannot be typical of interstellar…
In a new simple model I reconcile two contradictory views on the factors that determine the rate at which molecular clouds form stars -- internal structure vs. external, environmental influences -- providing a unified picture for the…
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…
We offer a new, more inclusive, picture of the local interstellar medium, where it is composed of a single, monolithic cloud that surrounds the Sun in all directions. Our study of velocities based on Mg II and Fe II ultraviolet absorption…
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…
Different studies have reported a power-law mass-size relation $M \propto R^q$ for ensembles of molecular clouds. In the case of nearby clouds, the index of the power-law $q$ is close to 2. However, for clouds spread all over the Galaxy,…
New extragalactic measurements of the cloud population-averaged star formation (SF) efficiency per freefall time $\rm\epsilon_{\rm ff}$ from PHANGS show little sign of theoretically predicted dependencies on cloud-scale virial level or…
The most recent observational evidence seems to indicate that giant molecular clouds are predominantly gravitationally unbound objects. In this paper we show that this is a natural consequence of a scenario in which cloud-cloud collisions…
Recent analytical and numerical models show that AGN outflows and jets create ISM pressure in the host galaxy that is several orders of magnitude larger than in quiescent systems. This pressure increase can confine and compress molecular…
Observational and theoretical evidence suggests that a substantial population of molecular clouds (MCs) appear to be unbound, dominated by turbulent motions. However, these estimations are made typically via the so-called viral parameter…
We investigate, through 2D MHD numerical simulations, the interaction of a uniform magnetic field oblique to a moving interstellar cloud. In particular we explore the transformation of cloud kinetic energy into magnetic energy as a result…
We present semi-analytic dynamical models for giant molecular clouds evolving under the influence of HII regions launched by newborn star clusters. In contrast to previous work, we neither assume that clouds are in virial or energetic…
We demonstrate that emulsion droplets stabilized by interfacial particles become unstable beyond a size threshold set by gravity. This holds not only for colloids but supra-colloidal glass beads, using which we directly observe the ejection…
Cold gas entering the central $1$ to $10^2$ pc of a galaxy fragments and condenses into clouds. The stability of the clouds determines whether they will be turned into stars or can be delivered to the central supermassive black hole (SMBH)…
Aims: We offer a new, simpler picture of the local interstellar medium, made of a single continuous cloud enveloping the Sun. This new outlook enables the description of a diffuse cloud from within and brings to light some unexpected…
The shape of the cold interstellar molecular gas is determined by several processes, including self-gravity, tidal force, turbulence, magnetic field, and galactic shear. Based on the 3D dust extinction map derived by Vergely et al., we…
We present an analysis of the large-scale molecular cloud structure and of the stability of clumpy structures in nearby molecular clouds. In our recent work, we identified a structural transition in molecular clouds by studying the…
We have mapped two molecular clouds at (l, b) = (3.2 degrees, + 0.3 degrees) and (l, b) = (5.4 degrees, -0.5 degrees) in 21-cm line and continuum emission. These clouds show unusually large velocity dispersions of more than 100 km/s (FWHM)…
We follow numerically the nonlinear evolution of the Parker instability in the presence of phase transitions from a warm to a cold HI interstellar medium in two spatial dimensions. The nonlinear evolution of the system favors modes that…
We compare the observed turbulent pressure in molecular gas, $P_\mathrm{turb}$, to the required pressure for the interstellar gas to stay in equilibrium in the gravitational potential of a galaxy, $P_\mathrm{DE}$. To do this, we combine…