Embedded Files
Relating spatially resolved optical attenuation, dust and gas in nearby galaxies
In this study, for the first time, we make a full comparison among dust surface density (Σdust), surface density of all gas components (ΣHI, ΣH2, Σgas) and optical attenuation derived independently from Balmer decrement (AV,BD) and SED fitting (AV,SED), at a spatial resolution lower than 0.5kpc. We investigate all nearby spiral galaxies with atomic and molecular gas maps, integral-field spectra and dust emission data.
Maps of observed and derived properties of NGC4321, one of the five galaxies in the sample. Grey points correspond to rejected pixels and smaller coloured points indicate pixels beyond the area that the SED-fitting was performed. Contours are taken from log Σdust maps.
We find that Σdust traces better the molecular and total gas content, rather than atomic gas. The correlations of Σdust with ΣH2 or with Σgas have the strongest significance and hold for individual galaxies as well as for the whole sample. The same is also found for the correlations of AV,BD with the gas components (see Fig. 5 in the paper for more details)
To investigate the correlation between the dust emission and the optical attenuation, we performed a full radiative transfer calculation assuming different dust-stars geometries (screen, slab, sandwich). Both AVBD and AVSEDyoung are affected by a combination of a screen dust component and a mixed dust and emitting material. On the contrary, AVSEDold as a function of the Σdust follows the models where sources and dust are mixed.
The AVBD (inferred by MUSE data) and the AVSEDyoung (by CIGALE SED-fitting) are in a very good agreement, with 88.6% of our data points differing by less than 0.5dex. SED-fitting derived AVSEDyoung could serve as a tracer of the attenuation in larger samples, where IFU observations might be more expensive and time-consuming.
The paper is accepted for publication on the Astronomy & Astrophysics journal. Until it is published you can find more of this work in the preprint:
Page updated
Google Sites
Report abuse