Related papers: Passage of a Gamma-Ray Burst Through a Molecular C…
Galactic cosmic rays (CRs) play a crucial role in ionisation, dissociation, and excitation processes within dense cloud regions where UV radiation is absorbed by dust grains and gas species. CRs regulate the abundance of ions and radicals,…
We study the structural evolution of turbulent molecular clouds under the influence of ionizing radiation emitted from a nearby massive star by performing a high resolution parameter study with the iVINE code. The temperature is taken to be…
Understanding the molecular content of galaxies is a critical problem in star formation and galactic evolution. Here we present a new method, based on a Stromgren-type analysis, to calculate the amount of HI that surrounds a molecular cloud…
We present a detailed calculation of the propagation of AGN-like ionizing radiation through the intergalactic space. We model the ionization state of absorbing clouds, and show that the universe will be more opaque above $4\,$Ryd than…
The formation of molecular clouds out of HI gas is the first step toward star formation. Its metallicity dependence plays a key role to determine star formation through the cosmic history. Previous theoretical studies with detailed chemical…
We present three-dimensional astrochemical simulations and synthetic observations of magnetised, turbulent, self-gravitating molecular clouds. We explore various galactic interstellar medium environments, including cosmic-ray ionization…
Context. Molecular clouds near the H II regions tend to harbor more luminous protostars. Aims. Our aim in this paper is to investigate whether or not radiation-driven implosion mechanism enhances luminosity of protostars near regions of…
We present the detection analysis of a diffuse molecular cloud at z$_{abs}$=2.4636 towards the quasar SDSS J1513+0352(z$_{em}\,\simeq$ 2.68) observed with the X-shooter spectrograph(VLT). We measure very high column densities of atomic and…
Cosmic-rays constitute the main ionising and heating agent in dense, starless, molecular cloud cores. We reexamine the physical quantities necessary to determine the cosmic-ray ionisation rate (especially the cosmic ray spectrum at E < 1…
Absorption line studies are essential to understanding the origin, nature, and impact of starburst-driven galactic outflows. Such studies have revealed a multiphase medium with a number of poorly-understood features leading to a need to…
In spite of accounting for only a small fraction of the mass of the Interstellar Medium (ISM), dust plays a primary role in many physical and chemical processes in the Universe. It is the main driver of extinction of radiation in the…
We present and test chemical models for three-dimensional hydrodynamical simulations of galaxies. We explore the effect of changing key parameters such as metallicity, radiation and non-equilibrium versus equilibrium metal cooling…
Photoionization modelling allows to follow the transport, the emergence, and the absorption of photons taking into account all important processes in nebular plasmas. Such modelling needs the spatial distribution of density, chemical…
A proper modelling of the cosmic-ray ionisation rate within gas clouds is crucial to describe their chemical evolution accurately. However, this modelling is computationally demanding because it requires the propagation of cosmic rays…
Observational studies indicate that the intergalactic medium (IGM) is highly ionized up to redshifts just over 6. A number of models have been developed to describe the process of reionization and the effects of the ionizing photons from…
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…
Interstellar chemistry is important for galaxy formation, as it determines the rate at which gas can cool, and enables us to make predictions for observable spectroscopic lines from ions and molecules. We explore two central aspects of…
We present a two-component gasdynamic model of an interstellar cloud embedded in a hot plasma. It is assumed that the cloud consists of atomic hydrogen gas, interstellar plasma is quasineutral. Hydrogen atoms and plasma protons interact…
Outflows from active galactic nuclei may be produced by absorption of continuum radiation by UV resonance lines of abundant metal ions, as observed in broad absorption line quasars (BALQs). The radiation pressure exerted on the metal ions…
We compare the HI column densities from Ly-alpha absorption to the metal column densities from X-ray absorption in gamma-ray burst (GRB) afterglows. Eight bursts of seventeen entering the sample, have significant extragalactic X-ray…