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DustPedia & Local Volume Legacy samples as benchmarks for dust evolution in galaxies
The purpose of this work is to show that by combining the DustPedia and LVL samples, we make a combined sample that includes galaxies of all morphological types, spanning a wide range of masses and star formation activity, well suited for constraining the dominant processes in the evolution of the dust content in the local Universe.
Following past indications, we now show clearly that the trend of log10(sMdust) versus log10(M∗) is not monotonic (see dashed-red curve; left panel). A positive correlation is found for galaxies with log10(M∗/M⊙) < 9.5, and a negative one for higher masses. The peak of the sMdust in local galaxies, and the change in the slope of the correlation, occurs at log10(M∗/M⊙)= 9.5. We also provide recipies that predict the average properties depending on galaxies' morphology (see colourful curve; right panel)
The sSFR of high-mass galaxies establishes a strong linear correlation with sMdust.(see dashed-red line; left panel). However, a large fraction of elliptical (E) and lenticular (S0) sources lie below the linear trend, in the low-sSFR regime. Low-mass spirals (Sa-Sdm), irregulars, and dwarf galaxies (Sm-Irr) lie in the high-sSFR regime, with an increased dispersion below the linear trend found for high-mass galaxies.
Grouping the galaxies in bins of stellar mass, we find that sMdust increases for low-mass galaxies that have a high sSFR (see black line; left panel), reaching a peak sMdust at log10(sSFR/yr−¹)≃−9.9. A similar behaviour is found by grouping the galaxies in bins of morphological type (see colourful curve; right panel), with the peak occurring at 0.1 dex higher log10(sSFR).
To better understand the trends we compared our results with evolutionary models that we computed using the one-zone dust evolution model chemevol. We varying specific free parameters in the code, such as the mass, age and other gas- and dust-related properties. The observed trends in the log10(sMdust)–log10(M∗), and the log10(sMdust)–log10(sSFR) planes can be interpreted mainly as the result of different initial gas mass budget and different galaxy ages, respectively.
The observed properties and trends of low-mass and highly star-forming Sm-Irr galaxies can be reproduced by the models if we assume a young galaxy age, a high efficiency for the photofragmentation rate of large grains, and/or a low grain-growth scaling factor in star-forming clouds.
You can find more of this work at the corresponding fortcoming article on the Astronomy & Astrophysics Journal:
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