KK 246: A Dwarf Galaxy with an Extended H I Disk in the Local Void
Kreckel, K.; van der Hulst, J. M.; van Gorkom, J. H.; van de Weygaert, R.; Peebles, P. J. E.
United States, Netherlands
Abstract
We have found that KK 246, the only confirmed galaxy located within the nearby Tully Void, is a dwarf galaxy with an extremely extended H I disk and signs of an H I cloud with anomalous velocity. It also exhibits clear misalignment between the kinematical major and minor axes, indicative of an oval distortion, and a general misalignment between the H I and optical major axes. We measure an H I mass of (1.05 ± 0.08) × 108 M sun, and an H I extent five times that of the stellar disk, one of the most extended H I disks known. We estimate a dynamical mass of 4.1 × 109 M sun, making this also one of the darkest galaxies known, with a mass-to-light ratio of 89. The relative isolation and extreme underdense environment make this an interesting case for examining the role of gas accretion in galaxy evolution.