Study of galaxies in the Lynx-Cancer void - I. Sample description

Abstract

The evolution of galaxies is influenced by the environment in which they reside. This effect should be strongest for the lowest-mass and -luminosity galaxies. To study dwarf galaxies in extremely low density environments, we have compiled a deep catalogue of dwarf galaxies in the nearby Lynx-Cancer void. This void hosts some of the most metal-poor dwarfs known to date. It borders the Local Volume at negative supergalactic Z(SGZ) coordinates and has a size of more than 16 Mpc. With a distance to its centre of only 18 Mpc, it is close enough to allow a search for the faintest dwarfs. Within the void 75 dwarf (−11.9 > M B > −18.0) and four subluminous (−18.0 > M B > −18.4) galaxies have been identified. We present the parameters of the void galaxies and a detailed analysis of the completeness of the catalogue as a function of magnitude and surface brightness. The catalogue appears almost complete to M B < −14 mag, but misses part of the fainter low surface brightness (LSB) face-on galaxies. This sample of void galaxies builds the basis of forthcoming observational studies that will provide insight into the main stellar population, H I mass-to-light ratio, metallicity and age for comparison with dwarfs in higher density regions. We briefly summarize the information on the unusual objects in the void and conclude that their concentration hints that voids are environments that are favourable for finding and studying unevolved dwarf galaxies.

XMP gas-rich dwarfs in nearby voids: results of SALT spectroscopy

“…One of the goals of selecting this void galaxy sample, was an opportunity to substantially increase the number of unusual void XMP very gas-rich dwarfs from the handful currently known. Most of the known prototype XMP dwarfs were found as a result of the systematic study of a hundred galaxies in the nearby Lynx-Cancer void (Pustilnik, Tepliakova 2011;Pustilnik et al 2016, and references therein).…”

THE STAR FORMATION HISTORIES OF LOCAL GROUP DWARF GALAXIES. I.HUBBLE SPACE TELESCOPE/WIDE FIELD PLANETARY CAMERA 2 OBSERVATIONS

“…The LG is not the lowest density environment in which dwarfs are formed (e.g., voids, Pustilnik et al 2002;Pustilnik & Tepliakova 2011), which may have affected their SFHs at early times. The interaction between a gas-rich dwarf and a massive galaxies can result in several effects, including the temporary enhancement of star formation, as is thought to be the case of the SMC and LMC (e.g., Besla et al 2007Besla et al , 2012Weisz et al 2013) and the eventual quenching of star formation (e.g., Teyssier et al 2012;Slater & Bell 2013).…”

STELLAR POPULATIONS AND STAR FORMATION HISTORY OF THE METAL-POOR DWARF GALAXY DDO 68∗

“…DDO 68 is especially appealing as candidate young galaxy because it is located at the periphery of the nearby Lynx-Cancer void (Pustilnik & Tepliakova 2011) and is at least 2 Mpc away from the closest bright galaxies (L > L , where L corresponds to M B = −19.6 for H = 72 km s −1 Mpc −1 ). Within the framework of hierarchical formation scenarios, the evolution of galaxies formed in voids could be quite different than in higher density environments because of a much lower probability of being subject to those processes (i.e.…”