DDO 161 and UGCA 319: an isolated pair of nearby dwarf galaxies
Rizzi, L.; Karachentsev, I. D.; Makarova, L. N.; Tully, R. B.; Karachentseva, V. E.; Shaya, E. J.
Russia, United States, Ukraine
Abstract
We report Hubble Space Telescope/Advanced Camera for Surveys observations of two nearby gas-rich dwarf galaxies: DDO 161 and UGCA 319. Their distances determined via the tip of the red giant branch are 6.03_{-0.21}^{+0.29} and 5.75 ± 0.18 Mpc, respectively. The galaxies form an isolated pair dynamically well separated from the nearest neighbours: KK 176 (7.28 ± 0.29 Mpc) and NGC 5068 (5.16 ± 0.21 Mpc). All four galaxies have a bulk spatial peculiar velocity towards the Virgo cluster of ∼158 ± 17 km s-1 in the Local Group rest frame and ∼330 km s-1 with respect to the cluster centre.