2024/11/15 by Sanjaya Paudel, Cristiano G. Sabiu, Suk-Jin Yoon +3 · 1 voice
Physics and Astronomy · #astro-ph.GA
paper · pdf · doi:10.3847/2041-8213/ad8f3c
We report the discovery of a rare isolated group of five dwarf galaxies located at z = 0.0086 (D = 36 Mpc). All member galaxies are star-forming, blue, and gas-rich with g-r indices ranging from 0.2 to 0.6 mag, and two of them show signs of ongoing mutual interaction. The most massive member of the group has a stellar mass that is half of the Small Magellanic Cloud stellar mass, and the median stellar mass of the group members is 7.87 × 107 M\odot. The derived total dynamical mass of the group is M\rm dyn = 6.02×1010 M\odot, whereas its total baryonic mass (stellar + HI) is 2.6×109 M\odot, which gives us the dynamical to baryonic mass ratio of 23. Interestingly, all galaxies found in the group are aligned along a straight line in the plane of the sky. The observed spatial extent of the member galaxies is 154 kpc, and their relative line-of-sight velocity span is within 75 km s-1. Using the spatially resolved optical spectra provided by DESI EDR, we find that three group members share a common rotational direction. With these unique properties of the group and its member galaxies, we discuss the possible importance of such a system in the formation and evolution of dwarf galaxy groups and in testing the theory of large-scale structure formation.