# Using dust, gas and stellar mass selected samples to probe dust sources and sinks in low metallicity galaxies

## TL;DR

This study combines galaxy samples with Herschel data and chemical models to investigate dust sources and sinks in low metallicity galaxies, revealing the importance of grain growth and reduced supernova dust contribution.

## Contribution

It introduces a comprehensive analysis of dust evolution in low metallicity galaxies using combined observational data and advanced chemical evolution models, highlighting the roles of inflows, outflows, and grain growth.

## Key findings

- Dust-poor, gas-rich galaxies require delayed star formation histories.
- Inflows and outflows are essential to explain metallicities at low gas fractions.
- Reduced supernova dust contribution and grain growth are key to matching observed dust masses.

## Abstract

We combine samples of nearby galaxies with Herschel photometry selected on their dust, metal, HI, and stellar mass content, and compare these to chemical evolution models in order to discriminate between different dust sources. In a companion paper, we used a HI-selected sample of nearby galaxies to reveal a sub-sample of very gas rich (gas fraction > 80 per cent) sources with dust masses significantly below predictions from simple chemical evolution models, and well below $M_d/M_*$ and $M_d/M_{gas}$ scaling relations seen in dust and stellar-selected samples of local galaxies. We use a chemical evolution model to explain these dust-poor, but gas-rich, sources as well as the observed star formation rates (SFRs) and dust-to-gas ratios. We find that (i) a delayed star formation history is required to model the observed SFRs; (ii) inflows and outflows are required to model the observed metallicities at low gas fractions; (iii) a reduced contribution of dust from supernovae (SNe) is needed to explain the dust-poor sources with high gas fractions. These dust-poor, low stellar mass galaxies require a typical core-collapse SN to produce 0.01 - 0.16 $M_{\odot}$ of dust. To match the observed dust masses at lower gas fractions, significant grain growth is required to counteract the reduced contribution from dust in SNe and dust destruction from SN shocks. These findings are statistically robust, though due to intrinsic scatter it is not always possible to find one single model that successfully describes all the data. We also show that the dust-to-metals ratio decreases towards lower metallicity.