Related papers: Grains in Photo-Ionized Environments
Aims: The production of molecular hydrogen and its deuterated forms onto carbonaceous dust grains is investigated in detail. The goal of this study is to estimate the importance of the chemistry occuring on grain surfaces for the…
Lyman-$\alpha$ absorption systems at $z \sim 3$ with $N_{HI} \ga 3 \times 10^{14}$ cm$^{-2}$ have been found to be enriched with a mean metallicity of $Z/Z_{\odot} \sim 10^{-2.5}$, and a large scatter in the metallicity. It is reasonable to…
The shape of the OB-star spectral energy distribution is a critical component in many diagnostics of the ISM and galaxy properties. We use single-star HII regions from the LMC to quantitatively examine the ionizing SEDs from widely…
We have designed an improved algorithm that enables us to simulate the chemistry of cold dense interstellar clouds with a full gas-grain reaction network. The chemistry is treated by a unified microscopic-macroscopic Monte Carlo approach…
The Orion Nebula is the defining galactic HII Region, and has been well studied over a broad range of wavelengths. The gas-phase metallicity is 2/3 of solar, close to the star cluster. Grains survive throughout. The Trapezium cluster's…
While the problem of grain alignment was posed more than 60 years ago the quantitative model of grain alignment that can account for the observed polarization arising from aligned grains has been formulated only recently. The quantitative…
Grain alignment theory suggests that grains should be aligned in circumstellar regions and the observational data available supports this conclusion. We discuss the alignment of grains via (1) magnetic relaxation, (2) mechanical processes,…
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 present ionization structures of IC 2003, a planetary nebula with [WR] central star, using a 1-D dusty photo-ionization code: "CLOUDY 17.03". The photo-ionization model is constrained by archival UV emission line fluxes,…
Fast and accurate approximations of gas cooling and heating functions are needed for hydrodynamic galaxy simulations. We use machine learning to analyze atomic gas cooling and heating functions computed by Cloudy in the presence of a…
The boundary conditions of the heliosphere are set by the ionization, density and composition of inflowing interstellar matter. Constraining the properties of the Local Interstellar Cloud (LIC) at the heliosphere requires radiative transfer…
A new scheme of radiation transfer for understanding infrared spectra of H II regions, has been developed. This scheme considers non-equilibrium processes (e. g. transient heating of the very small grains, VSG; and the polycyclic aromatic…
While marginal in mass terms, dust grains play an outsized role in both the physics and observation of the interstellar medium (ISM). However, explicit modelling of this ISM constituent remains uncommon in large cosmological simulations. In…
The temperatures of interstellar dust grains are analyzed using stochastic simulations, taking into account the grain composition and size and the discreteness of the photon flux. [...] The distribution of grain temperatures is calculated…
Thermal ionization is a critical process at temperatures T > 10 3 K, particularly during star formation. An increase in ionization leads to a decrease in nonideal magnetohydrodynamics (MHD) resistivities, which has a significant impact on…
An accurate treatment of the multiphase interstellar medium (ISM) in hydrodynamic galaxy simulations requires that we follow not only the thermal evolution of the gas, but also the evolution of its chemical state, including its molecular…
We present here a method to estimate physical parameters of novae systems using an extensive grid of photoionization models for novae. We use the photoionization code CLOUDY to construct grid of models covering a wide range of different…
The local cosmic-ray (CR) spectra are calculated for typical characteristic regions of a cold dense molecular cloud, to investigate two so far neglected mechanisms of dust charging: collection of suprathermal CR electrons and protons by…
Temperature fluctuations significantly affect microorganism growth and pest activities in grain pile, precise monitoring and forecasting temperature of stored grain are essential for maintaining the quality and safety of grain storage. This…
The James Webb Space Telescope has ushered in an era of abundant high-redshift observations of young stellar populations characterized by strong emission lines, motivating us to integrate nebular emission into the new Maraston stellar…