Related papers: Time-Dependent Ionization in Radiatively Cooling G…
We study the thermal structure of the neutral atomic (H {\small I}) interstellar medium across a wide range of metallicities, from supersolar down to vanishing metallicity, and for varying UV intensities and cosmic-ray ionization rates. We…
We extend the non-equilibrium model for the chemical and thermal evolution of diffuse interstellar gas presented in Richings et al. (2014) to account for shielding from the UV radiation field. We attenuate the photochemical rates by dust…
Investigating the reliability of the assumption of instantaneous chemical equilibrium (ICE) for calculating the CO number density in the solar atmosphere is of crucial importance for the resolution of the long-standing controversy over the…
We study hydrogen plasmas at magnetic fields B ~ 10^{12}-10^{13} Gauss, densities ~ 10^{-3}-10^3 g/cc and temperatures T ~ 10^{5.5}-10^{6.5} K, typical of photospheres of middle-aged cooling neutron stars. We construct an analytical free…
We present numerical simulations of the evolution of a supernova (SN) remnant expanding into a uniform background medium with density $n_H = 1.0$ cm$^{-3}$ and temperature of $10^4$ K. We include a dynamically evolving non-equilibrium…
While many astrophysical plasmas can be modelled successfully assuming ionisation and thermal equilibrium, in some cases this is not appropriate and a non-equilibrium approach is required. In nebulae around evolved stars the local elemental…
We present a code for modelling the ionization conditions of optically thin astrophysical gas structures. Given the gas hydrogen density, equilibrium temperature, elemental abundances, and the ionizing spectrum, the code solves the…
We study the problem of time-dependent photoionization of low density gaseous nebulae subjected to sudden changes in the intensity of ionizing radiation. To this end, we write a computer code that solves the full time-dependent energy…
Radiative processes play a pivotal role in shaping the thermal and chemical states of gas across diverse astrophysical environments, from the interstellar medium (ISM) to the intergalactic medium. We present a hybrid cooling model for…
Emission and absorption lines from elements heavier than helium (metals) represent one of our strongest probes of galaxy formation physics across nearly all redshifts accessible to observations. The vast majority of simulations that model…
In the work described here we investigate atomic processes leading to the formation of emission lines within the IRIS wavelength range at temperatures near $10^5$~K. We focus on (1) non-equilibrium and (2) density-dependent effects…
The nonthermal source abundances of elements play a crucial role in the understanding of cosmic ray (CR) phenomena from a few GeV up to several tens of EeV. We present a first systematic approach to describe the change of the abundances…
Equation of state for partially ionized carbon at temperatures T > ~ 10^5 K is calculated in a wide range of densities, using the method of free energy minimization in the framework of the chemical picture of plasmas. The free energy model…
We extend our time-dependent hydrogen ionization simulations of diffuse ionized gas to include metals important for collisional cooling and diagnostic emission lines. The combination of heating from supernovae and time-dependent collisional…
We present new cooling sequences, color-magnitude diagrams, and color-color diagrams for cool white dwarfs with pure hydrogen atmospheres down to an effective temperature $\te=1500$ K. We include a more detailed treatment of the physics of…
Context. The radiative energy balance in the solar chromosphere is dominated by strong spectral lines that are formed out of LTE. It is computationally prohibitive to solve the full equations of radiative transfer and statistical…
Reliably interpreting spectra from electron-ionized cosmic plasmas requires accurate ionization balance calculations for the plasma in question. However, much of the atomic data needed for these calculations have not been generated using…
Using N-body/hydrodynamic simulations, the influence of non-equipartition processes on the thermal and dynamical properties of cosmological baryonic gas is investigated. We focus on a possible departure from equilibrium between electrons,…
The energy transfer among the components in a gas determines its fate. Especially at low temperatures, inelastic collisions drive the cooling and the heating mechanisms. In the early Universe as well as in zero- or low- metallicity…
The non-linear dynamics of large ion clouds ($N \geq 256 $ ions) trapped in radio-frequency traps and coupled to laser-cooling give rise to a bistable behaviour of the temperature. Numerical simulations of the free evolution of a large…