Related papers: Star Formation in Self-Gravitating Turbulent Fluid…
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…
In the framework of the Theory of General Relativity, models of stars with an unusual equation of state $\rho c^2<0$, $P>0$ where $\rho$ is the mass density and $P$ is the pressure, are constructed. These objects create outside themselves…
We present a model that unifies the cosmic star formation rate (CSFR), obtained through the hierarchical structure formation scenario, with the (Galactic) local star formation rate (SFR). It is possible to use the SFR to generate a CSFR…
We study turbulent dissipation in the ISM and explore some implications for galaxy formation and evolution using 2D MHD numerical simulations of compressible fluids. The turbulent kinetic energy E_k is injected by stellar sources formed…
We derive an analytic prediction for the star formation rate in environments ranging from normal galactic disks to starbursts and ULIRGs in terms of the observables of those systems. Our calculation is based on three premises: (1) star…
We explain the large variety of star formation laws in terms of one single, simple law that can be inferred from the definition of the star formation rate and basic algebra. The resulting equation, $\SFR = \eff\ \Mcollapsing/\tauff$,…
Galactic gas-gas collisions involving a turbulent multiphase ISM share common ISM properties: dense extraplanar gas visible in CO, large linewidths (>= 50 km/s), strong mid-infrared H_2 line emission, low star formation activity, and strong…
We develop a simple model for a self-gravitating spherically symmetric relativistic star which begins to collapse from an initially static configuration by dissipating energy in the form of radial heat flow. We utilize the model to show how…
We investigate, through a series of numerical calculations, the evolution of dense cores that are accreting external gas up to and beyond the point of star formation. Our model clouds are spherical, unmagnetized configurations with fixed…
Stars form when filaments and dense cores in molecular clouds fragment and collapse due to self-gravity. In the most basic analyses of gravitational stability, the competition between self-gravity and thermal pressure sets the critical…
We address the cosmological evolution of violent gravitational instability in high-redshift, massive, star-forming galactic discs. To this aim, we integrate in time the equations of mass and energy conservation under self-regulated…
We investigate the properties of highly compressible turbulence, the compressibility arising from a small effective polytropic exponent $\gamma_e$ due to cooling. In the limit of small $\gamma_e$, the density jump at shocks is shown to be…
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…
The hypothesis that massive stars form by accretion can be investigated by simple analytical calculations that describe the effect that the formation of a massive star has on its own accretion flow. Within a simple accretion model that…
A large fraction of the gas in the Galaxy is cold, dense, and molecular. If all this gas collapsed under the influence of gravity and formed stars in a local free-fall time, the star formation rate in the Galaxy would exceed that observed…
Predicting the star formation rate (SFR) in galaxies is crucial to understand their evolution and morphology. To do so requires a fine understanding of how dense structures of gas are created and collapse. In that, turbulence and gravity…
Criteria for gravitational collapse of expanding shells in rotating, shearing galaxy disks were determined using three-dimensional numerical simulations in the thin shell approximation. The simulations were run over a grid of 7 independent…
We explore, through a simplified, semi-analytic model, the formation of dense clusters containing massive stars. The parent cloud spawning the cluster is represented as an isothermal sphere. This sphere is in near force balance between…
The origin of non-thermal motions in massive star forming regions can be ascribed to turbulence acting against the gravitational collapse, or to the self-gravity itself driving the rapid global collapse. The dependence between velocity…
Most stars form in dense star clusters deeply embedded in residual gas. These objects must therefore be seen as the fundamental building blocks of galaxies. With this contribution some physical processes that act in the very early and also…