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Related papers: The scattering and extinction properties of nanodi…

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Modeling extinction along anomalous/non-CCM sightlines, which are characterized by a broad $217.5 nm$ bump and steep far-ultraviolet (FUV) rise, is reported. The extinction along these sightlines, viz. {HD 210121}, {HD 204827}, {HD 29647}…

Solar and Stellar Astrophysics · Physics 2015-06-04 Rakesh K Rai , Shantanu Rastogi

The spectral energy distribution of quasars shows a sharp steepening of the continuum shortward of ~ 1100 A. The steepening could be a result of dust absorption. We present a dust extinction model which considers crystalline carbon grains…

Astrophysics · Physics 2009-11-11 L. Binette , A. C. Andersen , H. Mutschke , S. Haro-Corzo

We study the extinction properties of the composite dust grains, consisting of host silicate spheroids and graphite as inclusions, using discrete dipole approximation (DDA). We calculate the extinction cross sections of the composite grains…

Solar and Stellar Astrophysics · Physics 2015-06-17 Nisha Katyal , Ranjan Gupta , D B Vaidya

We modelled dust grain-size distributions for carbonaceous and silicates dust, as well as for free-flying iron nanoparticles in the environment of a $\gamma$-ray burst (GRB) afterglow, GRB 180325A. This GRB, at $z=2.2486$, has an…

High Energy Astrophysical Phenomena · Physics 2022-11-09 Elizabeth Cappellazzo , Tayyaba Zafar , Pablo Corcho-Caballero , David Alexander Kann , Ángel López-Sánchez , Adeel Ahmad

Modern data of the extinction curve from the ultraviolet to the near infrared are revisited to study the property of dust grains in the Milky Way (MW) and the Small Magellanic Cloud (SMC). We confirm that the graphite-silicate mixture of…

Astrophysics of Galaxies · Physics 2015-06-12 Takaya Nozawa , Masataka Fukugita

How dust scatters and absorbs starlight in the interstellar medium (ISM) contains important clues about the size and composition of interstellar dust. While the ultraviolet (UV) and visible interstellar extinction is well studied and can be…

Astrophysics of Galaxies · Physics 2015-06-19 Shu Wang , Aigen Li , B. W. Jiang

We explore the possibility that the steepening observed shortward of 1000A in the energy distribution of quasars may result from absorption by dust, being either intrinsic to the quasar environment or intergalactic. We find that a dust…

% context {Nano-diamonds are an enticing and enigmatic dust component yet their origin is still unclear. They have been unequivocally detected in only a few astronomical objects, yet they are the most abundant of the pre-solar grains, both…

Astrophysics of Galaxies · Physics 2022-01-26 A. P. Jones , Nathalie Ysard

The sizes of interstellar grains are widely distributed, ranging from a few angstroms to a few micrometers. The ultraviolet (UV) and optical extinction constrains the dust in the size range of a couple hundredth micrometers to several…

Astrophysics of Galaxies · Physics 2015-09-23 Shu Wang , Aigen Li , B. W. Jiang

Space Telescope Imaging Spectrograph (STIS) and archival International Ultraviolet Explorer (IUE) data were used to search for structure in the ultraviolet interstellar extinction curve. Between 1250 and 3200 A, in addition to the…

We model the ~1--19$\mum$ infrared (IR) extinction curve toward the Galactic Center (GC) in terms of the standard silicate-graphite interstellar dust model. The grains are taken to have a power law size distribution with an exponential…

Astrophysics of Galaxies · Physics 2015-06-16 Jian Gao , Aigen Li , B. W. Jiang

Reflectance and emissivity spectra of nanodiamonds powder were measured in a dedicated setup at temperatures up to 873 K. The spectra are characterised by presence of sharp bands due to surface-bound functional groups. Thermal desorption of…

Materials Science · Physics 2013-07-02 A. Maturilli , A. A. Shiryaev , I. I. Kulakova , J. Helbert

Observations of interstellar extinction and polarization indicate that the interstellar medium consists of aligned non-spherical dust grains which show variation in the interstellar extinction curve for wavelengths ranging from NIR to UV.…

Astrophysics · Physics 2009-09-15 Ranjan Gupta , Tadashi Mukai , D. B. Vaidya , Asoke K. Sen , Yasuhiko Okada

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…

Astrophysics · Physics 2009-06-23 D. B. Vaidya , Ranjan Gupta , T. P. Snow

The extinction curve of interstellar dust in the dense molecular cloud cores is crucial for understanding dust properties, particularly size distribution and composition. We investigate the infrared extinction law in four nearby isolated…

Astrophysics of Galaxies · Physics 2024-11-04 Jun Li , Bingqiu Chen , Biwei Jiang , He Zhao , Botao Jiang , Xi Chen

It is generally agreed that interstellar dust grains consist of two main components, namely, silicates and graphites. Some models, like MRN model, assume these grains to be homogeneous spheres following a power law size distribution. This…

Astrophysics of Galaxies · Physics 2009-03-30 Ashim K. Roy , Subodh K. Sharma , Ranjan Gupta

A composite dust grain model which simultaneously explains the observed interstellar extinction, polarization, IR emission and the abundance constraints, is required. We present a composite grain model, which is made up of a host silicate…

Solar and Stellar Astrophysics · Physics 2013-10-02 Nisha Katyal , Ranjan Gupta , D. B. Vaidya

The unusual extinction curves of SN 2010jl provide an excellent opportunity to investigate the properties of dust formed by core-collapse supernovae. By using a series of dust models with different compositions and grain size distributions,…

Solar and Stellar Astrophysics · Physics 2022-02-09 Jun Li , Jian Gao , Biwei Jiang , Zesen Lin

Context. Carbonaceous nano-grains play a fundamental role in the physico-chemistry of the interstellar medium (ISM) and especially of photon-dominated regions (PDRs). Their properties vary with the local physical conditions and affect the…

Astrophysics of Galaxies · Physics 2022-10-05 T. Schirmer , N. Ysard , E. Habart , A. P. Jones , A. Abergel , L. Verstraete

We study the near-infrared (NIR) scattering in LDN 1642, its correlation with the cloud structure, and the ability of dust models to simultaneously explain sub-millimetre emission, NIR extinction, and NIR scattering. We use observations…

Astrophysics of Galaxies · Physics 2020-11-25 Mika Juvela , Sharma Neha , Emma Mannfors , Mika Saajasto , Nathalie Ysard , Veli-Matti Pelkonen
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