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Modelling galaxy spectra in presence of interstellar dust – II. From the ultraviolet to the far-infrared

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TLDR
In this article, the spectral energy distributions (SEDs) of different morphological types of galaxies are derived by using a simple geometrical model for each type of galaxy, based on a robust model of chemical evolution that assumes a suitable prescription for gas infall, initial mass function, star formation rate and stellar ejecta.
Abstract
In this paper, we present spectrophotometric models for galaxies of different morphological type whose spectral energy distributions (SEDs) take into account the effect of dust in absorbing UV-optical light and re-emitting it in the infrared (IR). The models contain three main components: (i) the diffuse interstellar medium (ISM) composed of gas and dust whose emission and extinction properties have already been studied in detail by Piovan et al. (2006), (ii) the large complexes of molecular clouds (MCs) in which new stars are formed and (iii) the stars of any age and chemical composition. The galaxy models stand on a robust model of chemical evolution that assuming a suitable prescription for gas infall, initial mass function, star formation rate and stellar ejecta provides the total amounts of gas and stars present at any age together with their chemical history. The chemical models are taylored in such a way to match the gross properties of galaxies of different morphological type. In order to describe the interaction between stars and ISM in building up the total SED of a galaxy, one has to know the spatial distribution of gas and stars. This is made adopting a simple geometrical model for each type of galaxy. The total gas and star mass provided by the chemical model are distributed over the whole volume by means of suitable density profiles, one for each component and depending on the galaxy type (spheroidal, disk and disk plus bulge). The galaxy is then split in suitable volume elements to each of which the appropriate amounts of stars, MCs and ISM are assigned. Each elemental volume bin is at the same time source of radiation from the stars inside and absorber and emitter of radiation from and to all other volume bins and the ISM in between. They are the elemental seeds to calculate the total SED. Using the results for the properties of the ISM and the Single Stellar Populations (SSPs) presented by Piovan et al. (2006) we derive the SEDs of galaxies of different morphological type. First the technical details of the method are described and the basic relations driving the interaction between the physical components of the galaxy are presented. Second, the main parameters are examined and their effects on the SED of three prototype galaxies (a disk, an elliptical and a starburster) are highlighted. The final part of the paper is devoted to assess the ability of our galaxy models in reproducing the SEDs of a few real galaxies of the Local Universe.

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Journal ArticleDOI

galev evolutionary synthesis models – I. Code, input physics and web interface

TL;DR: The GALEV (Galev Evolutionary Evolutionary Models for Galaxies) model as mentioned in this paper describes the evolution of stellar populations in general, of star clusters as well as of galaxies, both in terms of resolved stellar populations and of integrated light properties over cosmological time-scales of ≥13 Gyr.
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Modeling the Pan-Spectral Energy Distribution of Starburst Galaxies. IV. The Controlling Parameters of the Starburst SED

TL;DR: In this article, the stellar spectral synthesis code Starburst99, the nebular modeling code MAPPINGS III and a one-dimensional dynamical evolution model of H II regions around massive clusters of young stars were combined to generate improved models of the spectral energy distribution (SED) of starburst galaxies.
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Ultraviolet dust attenuation in star‐forming galaxies – II. Calibrating the A(UV) versus LTIR/LUV relation

TL;DR: In this paper, the authors investigated the dependence of the total-infrared to UV luminosity ratio method for calculating the UV dust attenuation A(UV) from the age of the underlying stellar populations by using a library of spectral energy distributions for galaxies with different star formation histories.
Journal ArticleDOI

New colour–mass-to-light relations: the role of the asymptotic giant branch phase and of interstellar dust

TL;DR: In this paper, the authors use the latest Padova isochrones, with detailed modelling of the Thermally Pulsing AGB phase, to update theoretical colour-M/L relations in the optical and NIR and discuss the consequences for the estimated stellar masses in external galaxies.
References
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Journal ArticleDOI

SWIRE: The SIRTF Wide-area InfraRed Extragalactic Survey

TL;DR: The SIRTF Wide-area InfraRed Extragalactic Survey (SWIRE) as discussed by the authors is the largest survey to date to trace the evolution of galaxies, star-forming galaxies, evolved stellar populations, and AGN.
Journal ArticleDOI

Infrared Emission from Interstellar Dust. I. Stochastic Heating of Small Grains

TL;DR: In this article, 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 star-light photons results in high temperature transients, is presented.
Journal ArticleDOI

Synthetic properties of starburst galaxies

TL;DR: In this article, the results of an extensive grid of evolutionary synthesis models for populations of massive stars were presented, and the parameter space was chosen to correspond to conditions typically found in objects like giant H II regions, H II galaxies, blue compact dwarf galaxies, nuclear starbursts, and infrared luminous starburst galaxies.
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