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This work is the continuation of a series attempting to characterize the local warm ionized medium through both static and time dependent simulations. We build upon our three dimensional, observationally-derived simulation of the local…

Astrophysics of Galaxies · Physics 2025-06-24 Lewis McCallum , Kenneth Wood , Robert Benjamin , Dhanesh Krishnarao , Anna F. McLeod

The study of photoionised gas in planetary nebulae (PNe) has played a major role achieving, over the years, a better understanding of a number of physical processes pertinent to a broader range of fields than just PNe studies, ranging from…

Astrophysics · Physics 2009-11-11 Barbara Ercolano

A photoionized gas in thermal equilibrium can display a thermal instability, with 3 or more solutions in the multi-branch region of the S-shape curve giving the temperature versus the radiation-to-gas-pressure ratio. Many studies have been…

Astrophysics · Physics 2009-11-11 A. C. Goncalves , S. Collin , A. -M. Dumont , L. Chevallier

We present a method for including steady-state gas flows in the plasma physics code Cloudy, which was previously restricted to modeling static configurations. The numerical algorithms are described in detail, together with an example…

Astrophysics · Physics 2009-11-10 William J. Henney , S. Jane Arthur , Robin J. R. Williams , Gary J. Ferland

Diagnostic diagrams of forbidden lines have been a useful tool for observers in astrophysics for many decades now. They are used to obtain information on the basic physical properties of thin gaseous nebulae. Some diagnostic diagrams are in…

Instrumentation and Methods for Astrophysics · Physics 2015-06-18 Bastian Proxauf , Silvia Oettl , Stefan Kimeswenger

With the launch of the XRISM microcalorimeter mission, space-based X-ray observations will achieve a record spectral resolving power of $R\equiv E/\Delta E\sim$1200. With this resolving power, emission features associated with…

High Energy Astrophysical Phenomena · Physics 2025-07-31 Chamani M. Gunasekera , Peter A. M. van Hoof , Marios Chatzikos , Gary J. Ferland

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…

High Energy Astrophysical Phenomena · Physics 2015-06-16 J. García , E. E. Elhoussieny , M. A. Bautista , T. R. Kallman

We present hydrodynamic simulations of high-velocity clouds (HVCs) traveling through the hot, tenuous medium in the Galactic halo. A suite of models was created using the FLASH hydrodynamics code, sampling various cloud sizes, densities,…

Astrophysics of Galaxies · Physics 2015-05-28 Kyujin Kwak , David B. Henley , Robin L. Shelton

We describe two means by which XSTAR, a code which computes physical conditions and emission spectra of photoionized gases, has been parallelized. The first is pvm_xstar, a wrapper which can be used in place of the serial xstar2xspec script…

Instrumentation and Methods for Astrophysics · Physics 2009-01-23 Michael S. Noble , Li Ji , Andrew Young , Julia Lee

{It has recently been proposed that giant molecular complexes form at the sites where streams of diffuse warm atomic gas collide at transonic velocities.} {We study the global statistics of molecular clouds formed by large scale colliding…

Astrophysics · Physics 2009-11-13 P. Hennebelle , R. Banerjee , E. Vazquez-Semadeni , R. Klessen , E. Audit

The chemical composition of an extrasolar planet is fundamental to its formation, evolution and habitability. In this study, we explore a new way to measure the chemical composition of the building blocks of extrasolar planets, by measuring…

Ultraviolet and optical spectra of interstellar gas along the lines of sight to nearby stars have been interpreted by Redfield & Linsky (2008) and previous studies as a set of discrete warm, partially ionized clouds each with a different…

Astrophysics of Galaxies · Physics 2015-10-21 Seth Redfield , Jeffrey L. Linsky

We describe a new atomic and molecular database we developed for use in the spectral synthesis code Cloudy. The design of Stout is driven by the data needs of Cloudy, which simulates molecular, atomic, and ionized gas with kinetic…

Instrumentation and Methods for Astrophysics · Physics 2015-07-15 M. L. Lykins , G. J. Ferland , R. Kisielius , M. Chatzikos , R. L. Porter , P. A. M. van Hoof , R. J. R. Williams , F. P. Keenan , P. C. Stancil

The modeling of galaxy formation and reionization, two central issues of modern cosmology, relies on the accurate follow-up of the intergalactic medium (IGM). Unfortunately, owing to the complex nature of this medium, the differential…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-23 Alberto Manrique , Eduard Salvador-Solé

We study the formation of H2 in the ISM, using a modified version of the astrophysical magnetohydrodynamical code ZEUS-MP that includes a non-equilibrium treatment of the formation and destruction of H2. We examine two different…

Astrophysics · Physics 2008-11-26 S. C. O. Glover , M. -M. Mac Low

We introduce a novel approach to modelling the nebular emission from star-forming galaxies by combining the contributions from many HII regions incorporating loose trends in physical properties, random dust attenuation, a predefined Halpha…

We present a study of the ionization and thermal structure of neutral hydrogen clouds located in the Galactic halo, immersed in the extragalactic background radiation field, and supposed to be in pressure equilibrium with the surrounding…

Astrophysics · Physics 2009-10-22 Andrea Ferrara , George B. Field

We discuss models that astrochemists have developed to study the chemical composition of the interstellar medium. These models aim at computing the evolution of the chemical composition of a mixture of gas and dust under as- trophysical…

Astrophysics of Galaxies · Physics 2013-10-01 Valentine Wakelam , Herma M. Cuppen , Eric Herbst

We present a method for modelling star-forming clouds that combines two different models of the thermal evolution of the interstellar medium (ISM). In the combined model, where the densities are low enough that at least some part of the…

Solar and Stellar Astrophysics · Physics 2015-03-19 Matthew R. Bate , Eric R. Keto

We have developed a complete model of the hydrogen molecule as part of the spectral simulation code Cloudy. Our goal is to apply this to spectra of high-redshift star-forming regions where H2 absorption is seen, but where few other details…

Astrophysics · Physics 2009-11-13 Gargi Shaw , G. J. Ferland , R. Srianand , N. P. Abel