Dwarfs in nearby voids: results of SALT spectroscopy – II
Year: 2026
Type: article
Abstract: ABSTRACT We present results of spectroscopy with the Southern African Large Telescope of 35 objects from the Nearby Void Galaxy (NVG) sample, residing in the Local Volume (LV). The observed galaxies represent mainly the intermediate range of luminosities, with M$_{\rm B,tot}$ between –14.7 and –17.3 mag. For 28 galaxies, confirmed as residing in the nearby voids, we obtain spectra of the diverse quality. For all of them, we detect hydrogen and strong oxygen lines that allow us to derive parameter O/H in the observed H ii regions. For 16 galaxies, we detect the faint line [O iii]$\lambda$4363, which allows us to directly derive the electron temperature T$_{\rm e}$ and obtain their gas O/H by the direct method. For two objects without [O iii]$\lambda$4363 line, their value of 12+log(O/H) falls below $\sim$7.4 dex. To estimate their O/H, we use the empirical ‘strong line’ method of Izotov et al. For 10 objects without [O iii]$\lambda$4363 line, with the higher O/H, the modified version of the ‘semi-empirical’ method of Izotov and Thuan is used. It takes into account the effect of the excitation parameter O$_{\mathrm{3}2}$ on the empirically estimated T$_{\rm e}$. Of the 35 objects from the parent NVG sample, seven have mistaken radial velocities and do not reside in the nearby voids. We summarise the current status of the LV void galaxies spectral study. We also discuss the two LV strong metallicity-outliers, DDO215 and ESO252-001, resembling the unusual distant void galaxy VGS 12 with the compelling evidence of cold accretion.
Authors: S A Pustilnik, A Y Kniazev, A L Tepliakova, Y A Perepelitsyna
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $3,046
OpenAlex ID: W7140215443