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The generation of infrared (IR) radiation and the observed IR intensity distribution at wavelengths of 8, 24, and 100 micron in the ionized hydrogen region around a young, massive star is investigated. The evolution of the HII region is…

Astrophysics of Galaxies · Physics 2015-06-16 Yaroslav Pavlyuchenkov , Maria Kirsanova , Dmitry Wiebe

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…

Astrophysics of Galaxies · Physics 2026-02-12 G. La Mura , G. Mulas , M. A. Iatì , C. Cecchi-Pestellini , S. Rezaei , R. Saija

Gas cooling processes in the interstellar medium (ISM) are key to understanding how star-formation processes occur in galaxies. Far-infrared (FIR) fine-structure emission lines can be used as a tool to understand the gas conditions and…

Astrophysics of Galaxies · Physics 2023-12-06 Andrés Felipe Ramos Padilla , Lingyu Wang , F. F. S. van der Tak , Scott Trager

With the start of JWST observations, mid-infrared (MIR) emission features from polycyclic aromatic hydrocarbons (PAHs), H$_2$ rotational lines, fine-structure lines from ions, and dust continuum will be widely available tracers of gas and…

Astrophysics of Galaxies · Physics 2023-05-17 C. M. Whitcomb , K. Sandstrom , A. Leroy , J. -D. T. Smith

Studies measuring the chemical abundances of the neutral gas in star-forming galaxies (SFGs) require ionization correction factors (ICFs) to accurately measure their metal contents. In the work presented here we calculate newly improved…

Astrophysics of Galaxies · Physics 2020-04-01 Svea Hernandez , Alessandra Aloisi , Bethan L. James , Gary J. Ferland , Andrew J. Fox , Monica Tosi , Jason Tumlinson

The microwave spectral energy distribution of the dusty, diffuse H II region LPH 201.663+1.643 has been interpreted by others as tentative evidence for microwave emission from spinning dust grains. We present an alternative interpretation…

Astrophysics · Physics 2009-11-07 P. R. McCullough , R. R. Chen

Context. HI filaments are closely related to dusty magnetized structures that are observable in the far infrared (FIR). Recently it was proposed that the coherence of oriented HI structures in velocity traces the line of sight magnetic…

Astrophysics of Galaxies · Physics 2022-05-04 P. M. W. Kalberla , J. Kerp , U. Haud

We study the current discrepancy between the model-predicted and measured concentrations of Fe++ and Fe3+ in ionized nebulae. We calculate a set of photoionization models, updated with the atomic data relevant to the problem, and compare…

Astrophysics · Physics 2009-11-10 Monica Rodriguez , Robert H. Rubin

We report about a combined structural and magnetometric characterization of self-assembled magnetic nanoparticle arrays. Monodisperse iron oxide nanoparticles with a diameter of 20 nm were synthesized by thermal decomposition. The…

Mesoscale and Nanoscale Physics · Physics 2015-05-20 M. J. Benitez , D. Mishra , P. Szary , G. A. Badini Confalonieri , M. Feyen , A. H. Lu , L. Agudo , G. Eggeler , O. Petracic , H. Zabel

The formation of iron oxide nanoparticles (NPs) presents challenges such as efficiency losses and fine dust emissions in practical iron combustion systems, highlighting the need for deeper understanding of the formation mechanisms and…

Non-LTE line formation calculations of Fe I are performed for a small number of reference stars to investigate and quantify the efficiency of neutral hydrogen collisions. Using the atomic model that was described in previous publications,…

Astrophysics · Physics 2008-11-26 A. J. Korn , J. Shi , T. Gehren

The model is constructed of the propagation of gamma-ray burst radiation through a dense molecular cloud. The main processes of the interaction of the radiation with the interstellar gas are taken into account in the simulations: the…

High Energy Astrophysical Phenomena · Physics 2024-05-20 Aleksandr Nesterenok

The recent detection of the hydrocarbon anion C6H- in the interstellar medium has led us to investigate the synthesis of hydrocarbon anions in a variety of interstellar and circumstellar environments. We find that the anion/neutral…

Astrophysics · Physics 2009-11-13 T. J. Millar , C. Walsh , M. A. Cordiner , R. Ní Chuimín , Eric Herbst

The effects of background line opacity (line-blocking) in statistical equilibrium calculations for Fe in late-type stellar atmospheres have been investigated using an extensive and up-to-date model atom with radiative data primarily from…

Astrophysics · Physics 2016-08-30 Remo Collet , Martin Asplund , Frederic Thevenin

Modeling a promising carrier of the astronomically observed polycyclic aromatic hydrocarbon (PAH), infrared (IR) spectra of ionized molecules (C9H7) n+ were calculated based on density functional theory (DFT). In a previous study, it was…

Chemical Physics · Physics 2015-06-19 Norio Ota

M 2 has been claimed to posses three distinct stellar components that are enhanced in iron relative to each other. We use equivalent width measurements from 14 red giant branch stars from which Yong et al. detect a $\sim$0.8 dex wide,…

Solar and Stellar Astrophysics · Physics 2016-01-27 C. Lardo , A. Mucciarelli , N. Bastian

To find the spectral properties of AGNs in optical spectral band (around the Hb line) we constructed an Fe II template, that is covering Fe II emission from 4100 A to 5600 A. Using the new Fe II template we explored spectral properties of…

Cosmology and Nongalactic Astrophysics · Physics 2013-07-09 Luka C. Popovic , Jelena Kovacevic , Milan S. Dimitrijevic

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

The elaboration of multimodal nanoparticles stimulates tremendous interest owing to their numerous potentialities in many applicative fields like optoelectronics, photonics and especially bioimaging. The concomitant association of various…

Materials Science · Physics 2016-01-05 Jerome Fresnais , Elena Ishow , Olivier Sandre , Jean-Francois Berret

The magnetic behavior of $Fe_{3-x}O_4$ nanoparticles synthesized either by high-temperature decomposition of an organic iron precursor or low-temperature co-precipitation in aqueous conditions, is compared. Transmission electron microscopy,…

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