DustPedia and Local Volume Legacy samples as benchmarks for dust evolution in galaxies

Abstract

DustPedia and LVL are two samples representative of the local galaxy population, including in total 1011 unique objects of all morphological types, with a wide range of stellar masses ($M_*$) and star-formation activity, and a spectral coverage from the FUV to the FIR. The purpose of this work is to show that these samples cover two complementary ranges in $M_*$ and morphology, making them an ideal set for constraining the dominant processes in the evolution of the galactic dust content. Using the multiwavelength data provided by the two surveys, we fitted the galaxies' spectral energy distribution and estimated their physical properties, in particular the $M_*$, $sM_\mathrm{dust}=M_\mathrm{dust}/M_*$, and sSFR = SFR$/M_*$. By combining DustPedia and LVL, we highlight that the $\log_{10}(sM_{\rm dust})$-$\log_{10}(M_*)$ trend is not monotonic. Thanks to a large number of objects across a wide range of $M_*$, we have been able to fit two smoothly-joined linear correlations: a positive for $\log_{10}(M_{*}/$M$_\odot)\lesssim9.5$ (mainly LVL late spirals and irregulars), and a negative one for larger-mass, mainly DustPedia spirals (early types are distinct and more dispersed in the same mass regime). For $\log_{10}(M_{*}/$M$_\odot)>9.5$, we confirm a strong sM_{\rm dust}-sSFR correlation; dwarf galaxies, instead, lie below this trend, with a large scatter of $sM_{\rm dust}$, for -10.5<$\log_{10}$(sSFR/yr$^{-1}$)<-9.0. By using chemical evolution models we find that the observed $\log_{10}(sM_{\rm dust})$-$\log_{10}(M_{*})$ and $\log_{10}(sM_{\rm dust})$-$\log_{10}$(sSFR) trends can be interpreted mainly by variations in the initial gas mass budget and the galaxy ages, respectively. Low-mass Sm-Irr galaxies with low $sM_{\rm dust}$ and high sSFR can only be reproduced by the models by assuming high photofragmentation rate of large grains, and/or low grain-growth in clouds.