Related papers: Modelling Primordial Gas in Numerical Cosmology
Complex organic molecules (COMs) have been detected in the gas-phase in cold and lightless molecular cores. Recent solid-state laboratory experiments have provided strong evidence that COMs can be formed on icy grains through…
Methanol and its precursor formaldehyde are among the most studied organic molecules in the interstellar medium and are abundant in the gaseous and solid phases. We recently developed a model to simulate CO hydrogenation via H atoms on…
H2 formation in metal-free gas occurs via the intermediate H- or H2+ ions. Destruction of these ions by photodissociation therefore serves to suppress H2 formation. In this paper, I highlight the fact that several processes that occur in…
We perform SPH simulations of the collapse and fragmentation of low-mass cores having different initial levels of turbulence (alpha_turb=0.05,0.10,0.25). We use a new treatment of the energy equation which captures the transport of cooling…
The addition of metals to any gas can significantly alter its evolution by increasing the rate of radiative cooling. In star-forming environments, enhanced cooling can potentially lead to fragmentation and the formation of low-mass stars,…
Aims. We present a new sub-grid model, HYACINTH -- HYdrogen And Carbon chemistry in the INTerstellar medium in Hydro simulations -- for computing the non-equilibrium abundances of ${\rm H_2}$ and its carbon-based tracers, namely ${\rm CO}$,…
The first stars, galaxies, star clusters, and direct-collapse black holes are expected to have formed in low-mass ($\sim$$10^{5}-10^{9} ~ M_{\odot}$) haloes at Cosmic Dawn ($z \sim 10 - 30$) under conditions of efficient gas cooling,…
We study molecular hydrogen formation in and on solids. We construct a model with surface sites and bulk sites capable of describing (1) the motion and exchange of H and H_2 between surface and bulk, (2) the recombination of H and…
In the hierarchical structure formation model cosmic halos are supposed to form by accretion of smaller units along anisotropic direction, defined by large-scale filamentary structures. After the epoch of primary mass aggregation (which…
We study the impact of molecular (${\rm H_2}$) and atomic (HI) hydrogen cooling on the galaxy formation threshold. We calculate the fraction of dark matter (DM) halos that exceeds a critical mass required for star formation,…
We present a suite of six fully cosmological, three-dimensional simulations of the collapse of an atomic cooling halo in the early Universe. We use the moving-mesh code arepo with an improved primordial chemistry network to evolve the…
Energy-changing electron-hydrogen atom collisions are crucial to regulating the energy balance in astrophysical and laboratory plasmas and relevant to the formation of stellar atmospheres, recombination in H-II clouds, primordial…
Astrophysical models of primordial star formation require rate constants for three-body recombination as input. The current status of these rates for H2 due to collisions with H is far from satisfactory, with published rate constants…
The optical filaments found in many cooling flows in galaxy clusters consist of low density ($\sim 10^3 \pcc$) cool ($\sim 10^3$ K) gas surrounded by significant amounts of cosmic-ray and magnetic-field energy. Their spectra show…
We introduce a sub-grid model for the non-equilibrium abundance of molecular hydrogen in cosmological simulations of galaxy formation. We improve upon previous work by accounting for the unresolved structure of molecular clouds in a…
Formaldehyde is a key precursor in the formation routes of many complex organic molecules (COMs) in space. It is also an intermediate step in CO hydrogenation sequence that leads to methanol formation on the surface of interstellar grains…
We introduce a method for classical trajectory calculations to simulate collisions between atoms and large rigid asymmetric-top molecules. Using this method, we investigate the formation of molecule-helium complexes in buffer-gas cooling…
H2 is the simplest and the most abundant molecule in the ISM, and its formation precedes the formation of other molecules. Understanding the dynamical influence of the environment and the interplay between the thermal processes related to…
Experimental studies of electron mobilities in Neon as a function of the gas density have persistently shown mobilities up to an order of magnitude smaller than expected and predicted. A previously ignored mechanism (gas in--homogeneity…
We compute numerical simulations of spherical collapse triggered by a slow increase in external pressure. We compare isothermal models to models including cooling with a simple but self-consistent treatment of the coupling between gas,…