Y. Guo, C. Sengupta, T. C. Scott, P. Lagos, Y. Luo
Abstract
We present resolved Giant Metrewave Radio Telescope Hı observations of the high gas-phase metallicity dwarf galaxy WISEA J230615.06+143927.9 (z = 0.005) (hereafter J2306) and investigate whether it could be a Tidal Dwarf Galaxy (TDG) candidate. TDGs are observed to have higher metallicities than normal dwarfs. J2306 has an unusual combination of a blue g − r color of 0.23 mag, irregular optical morphology and high-metallicity (12 + log(O/H) = 8.68 ± 0.14), making it an interesting galaxy to study in more detail. We find J2306 to be an Hı rich galaxy with a large extended, unperturbed rotating Hı disk. Using our Hı data we estimated its dynamical mass and found the galaxy to be dark matter (DM) dominated within its Hı radius. The quantity of DM, inferred from its dynamical mass, appears to rule out J2306 as an evolved TDG. A wide area environment search reveals J2306 to be isolated from any larger galaxies which could have been the source of its high gas metallicity. Additionally, the Hı morphology and kinematics of the galaxy show no indication of a recent merger to explain the high-metallicity. Further detailed optical spectroscopic observations of J2306 might provide an answer to how a seemingly ordinary irregular dwarf galaxy achieved such a high level of metal enrichment.
Keywords
galaxies: abundances; galaxies: dwarf; galaxies: irregular; radio lines: galaxies; radio lines: ISM; Astrophysics - Astrophysics of Galaxies
Research in Astronomy and Astrophysics
Volume 24, Number 1, Page 11
2023 November
