We use a high-resolution cosmological simulation to predict the distribution of H I Lyα emission from the lowredshift (z . 0.5) intergalactic medium (IGM). Our simulation can be used to reliably compute the emission from optically thin regions of the IGM but not that of self-shielded gas. We therefore consider several models that bracket the expected emission from self-shielded regions. Most ga...

Recent observations by Chandra and XMM-Newton demonstrate that the central gas in "cooling flow" galaxy clusters has a mass cooling rate that decreases rapidly with decreasing temperature. This contrasts the predictions of a steady state cooling flow model. On the basis of these observational results, the gas can be in a steady state only if a steady temperature dependent heating mechanism is p...

Two kinetic models are proposed for high-temperature rarefied (or non-equilibrium) gas flows with radiation. One of the uses Boltzmann collision operator to model translational motion molecules, which has ability capture influence intermolecular potentials, while other adopts relaxation time approximations, higher computational efficiency. In modelling, not only transport coefficients such as s...

Some features of hydroand thermo-dynamics, as applied to atmospheres and to stellar structures, are puzzling: (1) the suggestion, first made by Laplace, that our atmosphere has an adiabatic temperature distribution, is confirmed for the lower layers, but the explanation for this is very controversial; (2) the standard treatment of relativistic thermodynamics does not favor a systematic treatmen...