Related papers: Modelling the Astronomical Silicate Features: I. O…
Studying the composition of dust in the interstellar medium (ISM) is crucial in understanding the cycle of dust in our galaxy. The mid-infrared spectral signature of amorphous silicates, the most abundant dust species in the ISM, is studied…
An accurate knowledge of the mineralogy (chemical composition and crystal structure) of the silicate dust in the interstellar medium (ISM) is crucial for understanding its origin in evolved stars, the physical and chemical processing in the…
We calculate the absorption efficiencies of composite silicate grains with inclusions of graphite and silicon carbide in the spectral range 5--25$\rm \mu m$. We study the variation in absorption profiles with volume fractions of inclusions.…
We present the Spitzer Space Telescope Infrared Spectrograph spectrum of the Orion A protostar HOPS-68. The mid-infrared spectrum reveals crystalline substructure at 11.1, 16.1, 18.8, 23.6, 27.9, and 33.6 microns superimposed on the broad…
We present evidence of a >10-sigma detection of the 10 micron silicate dust absorption feature in the spectrum of the gravitationally lensed quasar PKS 1830-211, produced by a foreground absorption system at redshift 0.886. We have examined…
Interstellar dust grain growth in dense clouds and protoplanetary disks, even moderate, affects the observed interstellar ice profiles as soon as a significant fraction of dust grains is in the size range close to the wave vector at the…
We model the 10 micron absorption spectra of nonspherical particles composed of amorphous silicate. We consider two classes of particles, compact ones and fractal aggregates composed of homogeneous spheres. For the compact particles we…
Model stellar atmospheres are fundamental tools for understanding stellar observations from interferometry, microlensing, eclipsing binaries and planetary transits. However, the calculations also include assumptions, such as the geometry of…
Interstellar grain mantles present in dense interstellar clouds are in constant exchange with the gas phase via accretion and desorption mechanisms such as UV, X-ray photodesorption, cosmic ray induced sputtering, grain thermal…
Wavelets have been used extensively for several years now in astronomy for many purposes, ranging from data filtering and deconvolution, to star and galaxy detection or cosmic ray removal. More recent sparse representations such ridgelets…
A wealth of data from the Herschel and Planck satellites and now from ALMA, revealing cold dust thermal emission, is available for astronomical environments ranging from interstellar clouds, cold clumps, circumstellar envelops, and…
The silicate cross section peak near 10um produces emission and absorption features in the spectra of dusty galactic nuclei observed with the Spitzer Space Telescope. Especially in ultraluminous infrared galaxies, the observed absorption…
In this paper we demonstrate that distinguishing between the polytypes of silicon carbide by means of infrared features in small-grain spectra is impossible. Therefore, the infrared spectra of carbon stars, unfortunately, do not provide a…
Cosmic-ray-induced sputtering is one of the important desorption mechanisms at work in astrophysical environments. The chemical evolution observed in high-density regions, from dense clouds to protoplanetary disks, and the release of…
The abundance of both amorphous and crystalline silicates in very small grains is limited by the fact that the 10 micron silicate emission feature is not detected in the diffuse ISM. On the basis of the observed IR emission spectrum for the…
The composite grain is made up of a host silicate spheroid and graphite inclusions. The extinction efficiencies of the composite spheroidal grains for three axial ratios are computed using the discrete dipole approximation (DDA). The…
Many estimation problems in astrophysics are highly complex, with high-dimensional, non-standard data objects (e.g., images, spectra, entire distributions, etc.) that are not amenable to formal statistical analysis. To utilize such data and…
We present a quantitative model for the infrared emission from dust in the diffuse interstellar medium. The model consists of a mixture of amorphous silicate grains and carbonaceous grains, each with a wide size distribution ranging from…
We have analyzed the 9.7 and ``18'' micron interstellar silicate absorption features along the line of sight toward four heavily extincted galactic WC-type Wolf-Rayet (WR) stars. We construct two interstellar extinction curves from 1.25 to…
In astrochemical exploration, infrared (IR) spectroscopy is vital for understanding the composition and structure of ice in various space environments. This article explores the impact of incident angles on IR spectroscopy, focusing on…