Gas-dust correlations in nearby galaxies: a case study of NGC 3184 and NGC 7793

TL;DR

This study investigates the relationship between gas and dust in two nearby spiral galaxies, revealing correlations and differences in dust properties across various galactic environments, aiding understanding of interstellar processes.

Contribution

It provides a detailed case study of gas-dust correlations in NGC 3184 and NGC 7793, highlighting differences in dust populations and gas components across galaxy types.

Findings

Positive correlation between gas and dust in both galaxies

Warm atomic gas dominates the total gas emission

NGC 7793 has a higher fraction of cold, large dust particles

Abstract

The study of gas-dust interactions occurring in the interstellar medium of a galaxy is essential for understanding various physical processes taking place within it. A comparison of such events at different locations corresponding to diverse astrophysical environments provides more insight into the star-formation as well as dust destruction conditions and time-scales. We present a case study for two galaxies: NGC 3184 and NGC 7793, which are typical examples of a `grand design spiral' and a `flocculent spiral', respectively. We investigate the gas-dust correlations at various spatially resolved locations within each galaxy, including spiral arms, using archival data. Moreover, we have segregated the neutral gas into wide (warm) and narrow (cold) velocity components to check the correlations with individual dust emission bands. We find a positive correlation between the gas and the dust, with the total atomic gas emission mainly dominated by its warm component in both the galaxies. We also find the dust population in NGC 7793 to have a greater fraction of emission coming from cold and diffuse, larger-sized dust particles as compared to NGC 3184. This nearby galaxy pilot study could serve as a template for similar studies of larger galaxy samples with analogous morphologies.