相关论文: Which thermal physics for gravitationally unstable…
Spatially homogeneous thermal equilibria of self-gravitating gas, being impossible otherwise, are nevertheless allowed in an expanding background accounting for Universe's expansion. Furthermore, a fixed density at the boundary of a…
It is generally recognized that the interstellar medium has a vast range of densities and temperatures. While these two properties are usually anticorrelated with each other, there are nevertheless variations in their product, i.e., the…
We discuss the temperature distribution in a two-dimensional, thermally unstable numerical simulation of the warm and cold gas in the Galactic disk, including the magnetic field, self-gravity, the Coriolis force, stellar energy injection…
We revisit the phenomenon of elements diffusion in the intergalactic medium (IGM) in clusters of galaxies. The diffusion is driven by gravity, concentration and temperature gradients. The latter cause thermal diffusion, which has been so…
Intergalactic space is filled with a pervasive medium of ionized gas, the Intergalactic Medium (IGM). A residual neutral fraction is detected in the spectra of Quasi-Stellar Objects at both low and high redshifts, revealing a highly…
Using Heisenberg's uncertainty principle it is shown that the gravitational stability condition for a crystalline vacuum cosmic space implies to obtain an equation formally equivalent to the relation first used by Gamow to predict the…
The conjecture that dark matter in galaxies is mostly cold fractal gas is developed in the more general context of the thermodynamics of the ideal isothermal gas subject to gravitational instability. This simple gas model already contains…
The use of statistical methods to model gravitational systems is crucial to physics practice, but the extent to which thermodynamics and statistical mechanics genuinely apply to these systems is a contentious issue. This paper provides new…
Thermal instability in the circum-galactic medium (CGM) can be responsible for the existence of cold clouds (e.g., high-velocity clouds) embedded in a hot diffuse medium (e.g., X-ray emitting gas). While many previous studies have analyzed…
In the absence of magnetic fields and cosmic rays, radiative cooling laws with a range of dependences on temperature affect the stability of interstellar gas. For about four and a half decades, astrophysicists have recognised the importance…
The thermal stability of rotating, stratified, unmagnetized atmospheres is studied by means of linear-perturbation analysis, finding stability, overstability or instability, depending on the properties of the gas distribution, but also on…
The radio frequency 1.4 GHz transition of the atomic hydrogen is one of the important tracers of the diffuse neutral interstellar medium. Radio astronomical observations of this transition, using either a single dish telescope or an array…
The interstellar medium (ISM) of galaxies very often contains a gas component that reaches the temperature of several million degrees, whose physical and chemical properties can be investigated through imaging and spectroscopy in the…
Using linear kinetic plasma theory the relation between electron density and magnetic field fluctuations for low-frequency plasma waves for Maxwellian background distribution functions of arbitrary temperatures in an uniform magnetic field…
A photoionized gas in thermal equilibrium can display a thermal instability, with 3 or more solutions in the multi-branch region of the S-shape curve giving the temperature versus the radiation-to-gas-pressure ratio. Many studies have been…
The existence of substellar cold H2 globules in planetary nebulae and the mere existence of comets suggest that the physics of cold interstellar gas might be much richer than usually envisioned. We study the case of a cold gaseous medium in…
Large reservoirs of cold (~ 10^4 K) gas exist out to and beyond the virial radius in the circumgalactic medium (CGM) of all types of galaxies. Photoionization modeling suggests that cold CGM gas has significantly lower densities than…
Gravity and thermal energy are universal phenomena which compete over the stabilization of astrophysical systems. The former induces an inward pressure driving collapse and the latter a stabilizing outward pressure generated by random…
We derive a general formulation of the laws of irreversible thermodynamics in the presence of electromagnetism and gravity. For the handling of macroscopic material media, we use as a guide the field equations and the Noether identities of…
Estimating the temperature and metal abundance of the intracluster and the intragroup media is crucial to determine their global metal content and to determine fundamental cosmological parameters. When a spatially resolved temperature or…