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# Dust emission profiles of DustPedia galaxies

Aleksandr Mosenkov (UGent) , Maarten Baes (UGent) , Ilse De Looze (UGent) , et al.
(2019) 622.
Author
Organization
Abstract
Most radiative transfer models assume that dust in spiral galaxies is distributed exponentially. In this paper our goal is to verify this assumption by analysing the two-dimensional large-scale distribution of dust in galaxies from the DustPedia sample. For this purpose, we have made use of Herschel imaging in five bands, from 100 to 500 μm, in which the cold dust constituent is primarily traced and makes up the bulk of the dust mass in spiral galaxies. For a subsample of 320 disc galaxies, we successfully performed a simultaneous fitting with a single Sérsic model of the Herschel images in all five bands using the multi-band modelling code GALFITM. We report that the Sérsic index n, which characterises the shape of the Sérsic profile, lies systematically below 1 in all Herschel bands and is almost constant with wavelength. The average value at 250 μm is 0.67 ± 0.37 (187 galaxies are fitted with n250 ≤ 0.75, 87 galaxies have 0.75 < n250 ≤ 1.25, and 46 - with n250 > 1.25). Most observed profiles exhibit a depletion in the inner region (at r < 0.3-0.4 of the optical radius r25) and are more or less exponential in the outer part. We also find breaks in the dust emission profiles at longer distances (0.5-0.6) r25 which are associated with the breaks in the optical and near-infrared. We assumed that the observed deficit of dust emission in the inner galaxy region is related to the depression in the radial profile of the HI surface density in the same region because the atomic gas reaches high enough surface densities there to be transformed into molecular gas. If a galaxy has a triggered star formation in the inner region (for example, because of a strong bar instability, which transfers the gas inwards to the centre, or a pseudobulge formation), no depletion or even an excess of dust emission in the centre is observed.
Keywords
Space and Planetary Science, Astronomy and Astrophysics

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## Citation

Chicago
Mosenkov, Aleksandr, Maarten Baes, S. Bianchi, V. Casasola, L. P. Cassarà, C. J. R. Clark, J. Davies, et al. 2019. “Dust Emission Profiles of DustPedia Galaxies.” Astronomy & Astrophysics 622.
APA
Mosenkov, A., Baes, M., Bianchi, S., Casasola, V., Cassarà, L. P., Clark, C. J. R., Davies, J., et al. (2019). Dust emission profiles of DustPedia galaxies. Astronomy & Astrophysics, 622.
Vancouver
1.
Mosenkov A, Baes M, Bianchi S, Casasola V, Cassarà LP, Clark CJR, et al. Dust emission profiles of DustPedia galaxies. Astronomy & Astrophysics. EDP Sciences; 2019;622.
MLA
Mosenkov, Aleksandr et al. “Dust Emission Profiles of DustPedia Galaxies.” Astronomy & Astrophysics 622 (2019): n. pag. Print.
@article{8614552,
abstract     = {Most radiative transfer models assume that dust in spiral galaxies is distributed exponentially. In this paper our goal is to verify this assumption by analysing the two-dimensional large-scale distribution of dust in galaxies from the DustPedia sample. For this purpose, we have made use of Herschel imaging in five bands, from 100 to 500 \ensuremath{\mu}m, in which the cold dust constituent is primarily traced and makes up the bulk of the dust mass in spiral galaxies. For a subsample of 320 disc galaxies, we successfully performed a simultaneous fitting with a single S{\'e}rsic model of the Herschel images in all five bands using the multi-band modelling code GALFITM. We report that the S{\'e}rsic index n, which characterises the shape of the S{\'e}rsic profile, lies systematically below 1 in all Herschel bands and is almost constant with wavelength. The average value at 250 \ensuremath{\mu}m is 0.67 {\textpm} 0.37 (187 galaxies are fitted with n250 \ensuremath{\leq} 0.75, 87 galaxies have 0.75 {\textlangle} n250 \ensuremath{\leq} 1.25, and 46 - with n250 {\textrangle} 1.25). Most observed profiles exhibit a depletion in the inner region (at r {\textlangle} 0.3-0.4 of the optical radius r25) and are more or less exponential in the outer part. We also find breaks in the dust emission profiles at longer distances (0.5-0.6) r25 which are associated with the breaks in the optical and near-infrared. We assumed that the observed deficit of dust emission in the inner galaxy region is related to the depression in the radial profile of the HI surface density in the same region because the atomic gas reaches high enough surface densities there to be transformed into molecular gas. If a galaxy has a triggered star formation in the inner region (for example, because of a strong bar instability, which transfers the gas inwards to the centre, or a pseudobulge formation), no depletion or even an excess of dust emission in the centre is observed.},
articleno    = {A132},
author       = {Mosenkov, Aleksandr and Baes, Maarten and Bianchi, S. and Casasola, V. and Cassar{\a}, L. P. and Clark, C. J. R. and Davies, J. and De Looze, Ilse and De Vis, P. and Fritz, J. and Galametz, M. and Galliano, F. and Jones, A. P. and Lianou, S. and Madden, S. C. and Nersesian, Angelos and Smith, M. W. L. and Tr\v{c}ka, Ana and Verstocken, Sam and Viaene, S{\'e}bastien and Vika, M. and Xilouris, E.},
issn         = {0004-6361},
journal      = {Astronomy \& Astrophysics},
language     = {eng},
publisher    = {EDP Sciences},
title        = {Dust emission profiles of DustPedia galaxies},
url          = {http://dx.doi.org/10.1051/0004-6361/201833932},
volume       = {622},
year         = {2019},
}

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