Examining the ionised gas in metal-poor environments is key to understanding the physical mechanisms regulating galaxy evolution. However, most of the previous studies of extragalactic regions rely on unresolved observations of gaseous structures. We aim to study the south-western, spatially resolved region of Leo A, one of the most studied gas-rich isolated galaxies in the Local Group. Using archival VIMOS-IFU/VLT data, we investigate its gaseous structure through optical emission lines to gain insights into the present-day drivers of gas physics in this dIrr, and we place constraints on the chemical evolution scenario responsible for its low chemical enrichment. We mapped the and flux distributions of the region, fully covered within the 27'' 27'' VIMOS field of view. Oxygen abundances were derived with the Tₑ-sensitive method, using the auroral emission-line detection, obtained by integrating spectral fibres of the data cube. The emission-line maps reveal that the strongest emission comes from the south-west region. Differences between the and distributions indicate a stratified distribution of ionic species, likely powered by the young star cluster at the nebular centre. HST/ACS photometry shows that the brightest star (sim15M_⊙) is in the centre of both the region and the young star cluster. Photoionisation production rates derived indicate that this star is able to sustain most of the ionisation budget to power the region, although subject to the assumed electron density. We derive an oxygen abundance of 12+łog () =7. 29 O/H dex, increasing to 7. 46 dex after correcting for temperature fluctuations. These values place Leo A on the low-mass end of the mass-metallicity relation. Chemical-evolution models indicate that, under constant accretion, the stellar-mass growth and metal enrichment over the last 10 Gyr are successfully reproduced by both the gas-regulator and leaky-box models. The distribution of young stars in this region reveals similar features to those of the region in the Sagittarius dIrr (SagDIG), supporting a picture in which the present-day evolution of Leo A is dominated by stellar feedback processes, associated with young stars in the cluster ionising the region studied in this work. The combination of mass-loss mechanisms and accretion events efficiently reproduces its chemical evolution, suggesting Leo A has evolved under a gas equilibrium regime across its lifetime.
Andrade et al. (Fri,) studied this question.