The bolometric and UV attenuation in normal spiral galaxies of the Herschel Reference Survey

The dust in nearby galaxies absorbs a fraction of the UV-optical-near-infrared radiation produced by stars. This energy is consequently re-emitted in the infrared. We investigate the portion of the stellar radiation absorbed by spiral galaxies from the Herschel Reference Survey (HRS) by modelling th...

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Bibliographic Details
Published in:Astronomy and astrophysics (Berlin) 2016-02, Vol.586, p.A13
Main Authors: Viaene, S., Baes, M., Bendo, G., Boquien, M., Boselli, A., Ciesla, L., Cortese, L., De Looze, I., Eales, S., Fritz, J., Karczewski, O. Ł., Madden, S., Smith, M. W. L., Spinoglio, L.
Format: Article
Language:English
Subjects:
Astrophysics
Attenuation
Dust
extinction
galaxies: ISM
Galaxy: fundamental parameters
Heating
infrared: ISM
Mathematical models
Modelling
Physics
Space telescopes
Spectral energy distribution
Spiral galaxies
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Summary:The dust in nearby galaxies absorbs a fraction of the UV-optical-near-infrared radiation produced by stars. This energy is consequently re-emitted in the infrared. We investigate the portion of the stellar radiation absorbed by spiral galaxies from the Herschel Reference Survey (HRS) by modelling their UV-to-submillimetre spectral energy distributions. Our models provide an attenuated and intrinsic spectral energy distribution (SED), from which we find that on average 32% of all starlight is absorbed by dust. We define the UV heating fraction as the percentage of dust luminosity that comes from absorbed UV photons and find this to be 56%, on average. This percentage varies with morphological type, with later types having significantly higher UV heating fractions. We find a strong correlation between the UV heating fraction and specific star formation rate and provide a power-law fit. Our models allow us to revisit the IRX – AFUV relations, and derive these quantities directly within a self-consistent framework. We calibrate this relation for different bins of NUV − r colour and provide simple relations to relate these parameters. We investigated the robustness of our method and conclude that the derived parameters are reliable within the uncertainties that are inherent to the adopted SED model. This calls for a deeper investigation of how well extinction and attenuation can be determined through panchromatic SED modelling.
ISSN:0004-6361
1432-0746
1432-0756
DOI:10.1051/0004-6361/201527586