H i Studies of Extremely Metal-Poor Dwarfs in Voids – I

We present and discuss the results of the Giant Metrewave Radio Telescope H i 21-cm line mapping for five isolated low-mass (Mbary~$(2–8)$× 10^7M$) eXtremely Metal Poor dwarfs [12+$log$(O/H) = 7.13–7.28], selected from the nearby void galaxy sample. All the studied void dwarfs show disturbed morphology in the H i maps with the angular resolutions of $~ 11$ to $~ 40\,{ arcsec}$. We examine the H i morphology and velocity field and the relative orientation of their stellar and gas body spins. We discuss the overall non-equilibrium state of their gas and the possible origin and evolution of the studied void dwarfs. The most straightforward interpretation of the ubiquitous phenomenon of the gas component non-equilibrium state in these and similar void dwarfs is the cold accretion from the void filaments and/or minor mergers. The cold gas accretion in voids could be linked to the presence of small filaments that constitute the substructure of voids.