Volume 599, March 2017
|Number of page(s)||22|
|Published online||01 March 2017|
The Herschel Exploitation of Local Galaxy Andromeda (HELGA)
VII. A SKIRT radiative transfer model and insights on dust heating⋆
1 Sterrenkundig Observatorium, Universiteit Gent, Krijgslaan 281, 9000 Gent, Belgium
2 Tartu Observatory, Observatooriumi 1, 61602 Tõravere, Estonia
3 UK ALMA Regional Centre Node, Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK
4 KU Leuven, Instituut voor Sterrenkunde, Celestijnenlaan 200D 2401, 3001 Leuven, Belgium
5 Vrije Universiteit Brussel, Department of Physics and Astrophysics, Pleinlaan 2, 1050 Brussels, Belgium
6 Unidad de Astronomía, Fac. Cs. Básicas, Universidad de Antofagasta, Avda. U. de Antofagasta 02800, Antofagasta, Chile
7 Laboratoire d’Astrophysique de Marseille – LAM, Université d’Aix-Marseille & CNRS, UMR 7326, 38 rue F. Joliot-Curie, 13388 Marseille Cedex 13, France
8 Department of Physics and Astronomy, University of California, Irvine CA 92697, USA
9 Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK
10 Istituto di Astrofisica e Planetologia Spaziali (INAF-IAPS), via Fosso del Cavaliere 100, 00133 Roma, Italy
11 Instituto de Radioastronomía y Astrofísica, IRAf, UNAM, Campus Morelia, A.P. 3-72, C.P. 58089, Mexico
12 European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching-bei-München, Germany
13 Laboratoire AIM, CEA, Université Paris Diderot, IRFU/Service d’Astrophysique, Bat. 709, 91191 Gif-sur-Yvette, France
14 School of Physics and Astronomy, Cardiff University, Queens Buildings, The Parade, Cardiff CF24 3AA, UK
Received: 5 July 2016
Accepted: 26 September 2016
The radiation from stars heats dust grains in the diffuse interstellar medium and in star-forming regions in galaxies. Modelling this interaction provides information on dust in galaxies, a vital ingredient for their evolution. It is not straightforward to identify the stellar populations heating the dust, and to link attenuation to emission on a sub-galactic scale. Radiative transfer models are able to simulate this dust-starlight interaction in a realistic, three-dimensional setting. We investigate the dust heating mechanisms on a local and global galactic scale, using the Andromeda galaxy (M 31) as our laboratory. We have performed a series of panchromatic radiative transfer simulations of Andromeda with our code SKIRT. The high inclination angle of M 31 complicates the 3D modelling and causes projection effects. However, the observed morphology and flux density are reproduced fairly well from UV to sub-millimeter wavelengths. Our model reveals a realistic attenuation curve, compatible with previous, observational estimates. We find that the dust in M 31 is mainly (91% of the absorbed luminosity) heated by the evolved stellar populations. The bright bulge produces a strong radiation field and induces non-local heating up to the main star-forming ring at 10 kpc. The relative contribution of unevolved stellar populations to the dust heating varies strongly with wavelength and with galactocentric distance. The dust heating fraction of unevolved stellar populations correlates strongly with NUV−r colour and specific star formation rate. These two related parameters are promising probes for the dust heating sources at a local scale.
Key words: galaxies: individual: M 31 / galaxies: ISM / infrared: ISM / galaxies: fundamental parameters / dust, extinction / radiative transfer
© ESO, 2017
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