We present results from an ongoing programme to study the dust and ionized gas in E/S0 galaxies with dust lanes. Our data, together with results from previous studies of E/S0 galaxies, are used to demonstrate the close relationship between these two components. This relationship is discussed in light of our current understanding of the nature and origin of the interstellar medium (ISM), and in particular in the context of the interplay between the different multi‐temperature components. We show that focusing on dust obscured regions as tracers of the ISM, and on their properties, serves as independent evidence for the external origin of the dust and ionized gas.

We present our H α observations of 11 isolated southern galaxies: SDIG, PGC 51659, E 222-010, E 272-025, E 137-018, IC 4662, Sag DIG, IC 5052, IC 5152, UGCA 438, and E 149-003, with distances from 1 to 7 Mpc. We have determined the total H α fluxes from these galaxies. The star formation rates in these galaxies range from 10 −1 (IC 4662) to 10 −4 M ⊙ yr −1 (SDIG) and the gas depletion time at the observed star formation rates lies within the range from 1/6 to 24 Hubble times H −1 0 .

In the framework of an ongoing project aimed at searching for and studying eXtremely Metal-Poor (XMP) very gas-rich blue dwarfs in nearby voids, we conducted spectroscopy with the 11-m Southern African Large Telescope (SALT) of 26 candidates, preselected in the first paper of this series (PEPK19). For 23 of them, we detected Oxygen lines, allowing us to estimate the gas O/H ratio. For ten of them, the oxygen abundance is found to be very low, in the range of 12+log(O/H)=6.95-7.30 dex. Of those, four void dwarfs have 12+log(O/H) < 7.19, or Z < Z /30. For the majority of observed galaxies, the faint line [Oiii]λ4363Å used to estimate O/H with the direct T e method appeared either too noisy or was not detected. We therefore use the semiempirical method of Izotov & Thuan (2007) for these spectra, or, when applicable, the new 'Strong line' method of Izotov et al. (2019b). We present and discuss the results for all void dwarfs observed in this work. We also compare their O/H values with O/H values of ∼140 void galaxies available from our recent papers. We address the properties of the newly found unusual void XMP dwarfs and compare them with those for ten known prototype void XMP objects. The latter small group is outstanding based on their very small mass fraction of stars (only 0.01-0.02 of the baryonic mass), the blue colours of stars in the outer body (indicating a non-cosmological age for the main star-forming episode), and the low gas metallicity (several times lower than expected for their luminosity).