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We present a high-resolution spectral study of Fe L-shell extinction by the diffuse interstellar medium (ISM) in the direction of the X-ray binaries Cygnus X-1 and GX 339-4, using the XMM-Newton reflection grating spectrometer. The majority…

Photoionization models of the giant HII region 30 Doradus are built and confronted to available UV, optical, IR (ISO) and radio spectra, under black-body or CoStar SEDs for the primary source and various density distributions for the…

Astrophysics · Physics 2009-11-13 Y. G. Tsamis , D. Pequignot

Dust particles play a major role in the formation, evolution and chemistry of interstellar clouds, stars and planetary systems. Commonly identified forms include amorphous and crystalline carbon-rich particles and silicates. Also present in…

Astrophysics of Galaxies · Physics 2019-09-25 P. J. Sarre

Observational evidence seems to indicate that the depletion of interstellar carbon into dust shows rather wide variations and that carbon undergoes rather rapid recycling in the interstellar medium (ISM). Small hydrocarbon grains are…

Constraining the physical conditions of the ionized media in the vicinity of an active supermassive black hole (SMBH) is crucial to understanding how these complex systems operate. Metal emission lines such as iron (Fe) are useful probes to…

Astrophysics of Galaxies · Physics 2024-01-08 Denimara Dias dos Santos , Swayamtrupta Panda , Alberto Rodríguez-Ardila , Murilo Marinello

We perform a homogeneous analysis of the Fe/Ni abundance ratio in eight Galactic planetary nebulae (PNe) and three Galactic H II regions that include the Orion nebula, where we study four nebular zones and one shocked region. We use [Fe…

Solar and Stellar Astrophysics · Physics 2016-01-20 Gloria Delgado-Inglada , Adal Mesa-Delgado , Jorge García-Rojas , Mónica Rodríguez , César Esteban

We investigate the air-induced degradation of few-layer hafnium diselenide (HfSe$_2$) through combined experimental and theoretical approaches. AFM and SEM reveal the formation of selenium-rich spherical features upon ambient exposure,…

Measurements of [Fe/H] and [$\alpha$/Fe] can probe the minor merging history of a galaxy, providing a direct way to test the hierarchical assembly paradigm. While measurements of [$\alpha$/Fe] have been made in the stellar halo of the Milky…

Astrophysics of Galaxies · Physics 2019-06-19 Ivanna Escala , Evan N. Kirby , Karoline M. Gilbert , Emily C. Cunningham , Jennifer Wojno

We investigate the physical properties of molecular hydrogen (H2) in isolated and interacting disk galaxies with different masses and Hubble types by using chemodynamical simulations with H2 formation on dust grains and dust growth and…

Astrophysics of Galaxies · Physics 2017-03-08 Kenji Bekki

HCN molecules serve as an important tracer for chemical evolution of elemental nitrogen in the regions of star and planet formation. This is largely explained by the fact that N atoms and N$_2$ molecules are poorly accessible for the…

Context. Neutral atomic hydrogen (HI) absorption lines can be used to probe the cold neutral medium (CNM) at high Galactic latitudes. Cold HI with a significant optical depth from the GASKAP-HI survey is found to be located predominantly if…

Astrophysics of Galaxies · Physics 2025-11-26 P. M. W. Kalberla

Nanoparticles of iron were prepared in distilled water using very thin iron wires and sheets, by the electro-exploding wire technique. Transmission electron microscopy reveals the size of the nanoparticles to be in the range 10 to 50 nm.…

Materials Science · Physics 2007-05-23 Abdullah Alqudami , S. Annapoorni , Subhalakshmi Lamba , P C Kothari , R K Kotnala

We investigate the impact of anomalous microwave emission (AME) on the radio-millimeter spectral energy distribution for three typical interstellar medium (ISM) conditions surrounding star-forming regions -- cold neutral medium, warm…

Astrophysics of Galaxies · Physics 2022-09-21 Ilsang Yoon

Iron, the Universe's most abundant refractory element, is highly depleted in both circumstellar and interstellar environments, meaning it exists in solid form. The nature of this solid is unknown. In this Letter, we provide evidence that…

We consider the depletion of elements from the interstellar gas onto a population of very small dust grains. Adopting a grain model in which of order 4% of the cosmic C abundance is in grains with radii <= 10 Angstroms, we find that the…

Astrophysics · Physics 2009-10-31 Joseph C. Weingartner , Bruce T. Draine

In the denser and colder ($\leq$20 K) regions of the interstellar medium (ISM), near-infrared observations have revealed the presence of sub-micron sized dust grains covered by several layers of H\textsubscript{2}O-dominated ices and…

Astrophysics of Galaxies · Physics 2020-11-25 Stefano Ferrero , Lorenzo Zamirri , Cecilia Ceccarelli , Arezu Witzel , Albert Rimola , Piero Ugliengo

We present a detailed study of the magnetic behavior of iron-oxide (gamma-Fe2O3 and Fe3O4) nanoparticles constituents of ferrofluids (FF's) with average particle sizes <d> = 2.5 and 10 nm. The particles were dispersed in the frozen liquid…

Materials Science · Physics 2011-03-24 G. F. Goya , S. L. Gómez , S. M. Shibli

The trending term "filament" is extensively used in the interstellar medium (ISM) and the star formation community, and is believed to be one of the most important objects that gauge molecular cloud and star formation. However, the physical…

Astrophysics of Galaxies · Physics 2024-05-01 Ka Ho Yuen , Ka Wai Ho , Chi Yan Law , Avi Chen

A number of metal-based nanopowders such kinds as Fe, Co, Fe/Co alloy, Fe/C, Fe/organic shell were successfully produced by aerosol synthesis method. The mechanism of nanoparticles formation and the influence of experimental parameters on…

Materials Science · Physics 2007-08-13 E. S. Vasilieva , O. V. Tolochko , V. E. Yudin , D. Kim , D. -W. Lee

We present new ultra-metal-poor (UMP) stars parameters with [Fe/H]<-4.0 based on line-by-line non-local thermodynamic equilibrium (NLTE) abundances using an up-to-date iron model atom with a new recipe for non-elastic hydrogen collision…

Solar and Stellar Astrophysics · Physics 2017-10-11 Rana Ezzeddine , Anna Frebel , Bertrand Plez