Related papers: Missing Fe: hydrogenated iron nanoparticles
Nanometer- and micrometer-sized solid particles play an important role in the evolutionary cycle of stars and interstellar matter. The optical properties of cosmic grains determine the interaction of the radiation field with the solids,…
Knowledge of the molecular component of the ISM is fundamental to understand star formation. The H2 component appears to dominate the gas mass in the inner parts of galaxies, while the HI component dominates in the outer parts. Observation…
A number of very small isolated HII regions have been discovered at projected distances up to 30 kpc from their nearest galaxy. These HII regions appear as tiny emission line objects in narrow band images obtained by the NOAO Survey for…
Films of metal-insulator nanogranular composites M$_x$D$_{100-x}$ with different composition and percentage of metal and dielectric phases (M = Fe, Co, CoFeB; D = Al$_2$O$_3$, SiO$_2$, LiNbO$_3$; x $\approx$ 15-70 at.%) are investigated by…
Active galactic nuclei (AGN) have Fe II emission from the broad line region (BLR) that differs greatly in strength from object to object. We examine the role of the total and gas-phase iron abundance in determining Fe II strength. Using AGN…
Following from our recent work, we present a detailed analysis of star-formation and interstellar medium (ISM) scaling relations, done on a representative sample of nearby galaxies. H$\alpha$ images are analysed in order to derive the…
The depletion of iron and sulphur into dust in the interstellar medium and the exact nature of interstellar amorphous silicate grains is still an open question. We study the incorporation of iron and sulphur into amorphous silicates of…
We have carried out a spectroscopic survey of several B, Be, and shell stars in optical and near-infrared regions. Line profiles of the H-alpha line and of selected Fe II and O I lines are presented.
The oxidation state of iron in the interstellar medium (ISM) can provide constraints on the processes that operated on material in the protosolar disk. We used synchrotron-based X-ray absorption spectra of several mineral standards and two…
We report on our first results from a mid-infrared spectroscopic study of ISM features in a sample of deeply obscured ULIRG nuclei using the InfraRed Spectrograph (IRS) on the Spitzer Space Telescope. The spectra are extremely rich and…
We report the chemical synthesis of Fe-core/Au-shell nanoparticles by a reverse micelle method, and the investigation of their growth mechanisms and oxidation-resistant characteristics. The core-shell structure and the presence of the Fe &…
We report experiments on surface nanopatterning of Si targets which are irradiated with 2 keV Ar + ions impinging at near-glancing incidence, under concurrent co-deposition of Au impurities simultaneously extracted from a gold target by the…
Interstellar dust grains are often aligned. If the grain alignment direction varies along the line of sight, the thermal emission becomes circularly-polarized. In the diffuse interstellar medium, the circular polarization at far-infrared…
Employing aberration-corrected scanning transmission electron microscopy (STEM), we meticulously investigated the intrinsic chemical heterogeneity of Fe1+yTe, Fe1+yTe0.8Se0.2, and Fe1+yTe0.5Se0.5. Comprehensive analysis reveals the presence…
Infrared (IR) emission spectra are calculated for dust composed of mixtures of amorphous silicate and graphitic grains, including varying amounts of polycyclic aromatic hydrocarbon (PAH) particles. The models are constrained to reproduce…
We present a method for calculating the infrared emission from a population of dust grains heated by starlight, including very small grains for which stochastic heating by starlight photons results in high temperature transients. Because…
Comparison of the ISM properties of a wide range of metal-poor galaxies with normal metal-rich galaxies reveals striking differences. We find that the combination of the low dust abundance and the active star formation results in a very…
We apply the atom-atom potentials to molecular crystals of iron (II) complexes with bulky organic ligands. The crystals under study are formed by low-spin or high-spin molecules of Fe(phen)$_{2}$(NCS)$_{2}$ (phen = 1,10-phenanthroline),…
Banerji et al. (2009) suggested that top-heavy stellar Initial Mass Functions (IMFs) in galaxies may arise when the interstellar physical conditions inhibit low-mass star formation, and they determined the physical conditions under which…
Using IRAM 30m, SEST 15m, and Nancay radiotelescopes, we have gathered the 1mm continuum emission, spectra of the J=1--0 CO line and of the HI line at 21cm for two samples of IRAS galaxies. Using these data, we have estimated the HI masses,…