Moses K. Mogotsi | Searcharxiv

arXiv2026

Tracing neutral hydrogen in UGCA 320: A MHONGOOSE perspective on an edge-on dwarf galaxy in a group environment

We present a detailed analysis of the neutral atomic gas (HI) in the dwarf galaxy UGCA 320, observed with the MeerKAT telescope as part of the MHONGOOSE (MeerKAT HI Observations of Nearby Galactic Objects: Observing Southern Emitters) programme. In a small group consisting of three dwarf galaxies, all of which contain HI, it is the most massive. Detailed kinematic modelling shows that UGCA 320 contains a substantial amount of (kinematically) anomalous gas (>=20%), at least ~30% of which is likely the result of a tidal interaction with its neighbour UGCA 319. It also reveals that UGCA 320 likely harbours a star-formation driven outflow, and that ~10% of its HI is extra-planar and has a filamentary structure. Although UGCA 320 aligns with established scaling relations from the literature, its neutral hydrogen content is notably complex - shaped by its immediate environment. This underscores the importance of deep, resolved observations and detailed kinematic analyses to capture the nuances of galaxy evolution.

astro-ph.GA↗

arXiv2025

Stars and ionized gas in UGCA 320: a nearby gas-rich, dwarf Irregular galaxy

UGCA 320 is a gas-rich dwarf irregular galaxy which belongs to a nearby, relatively isolated group of dwarf galaxies. Here, we combine multi-band HST imaging data with deep long-slit SALT/RSS and integral-field VLT/MUSE spectral data to study the stellar and ionized gas components of UGCA 320. Our imaging data analysis reveals a very blue (V-I~0.1 mag), flattened radial colour profile. We detect an abundance of ionized gas in UGCA 320 powered mostly by recent star formation. The stellar disc in UGCA 320 is populated predominantly by young (~120 Myr) and metal-poor (~15-30 per cent solar metallicity) stars and it rotates in the same sense as the ionized gas disc but with higher rotation velocities, and possibly in different planes. Our analysis reveals a sharp transition in the kinematic properties of the discs at radius ~10" (~0.3 kpc) and distortions in the outer disc region. We show that these features are consistent with a recent tidal interaction most likely with its close neighbour - UGCA 319. We discuss our results in the context of interacting dwarf galaxies and also show that similar inferences can be made independently from the long-slit data analysis as with the integral-field data.

astro-ph.GA↗