Author ORCID Identifier
Document Type
Article
Publication Date
9-30-2024
Abstract
We present the discovery of a low-mass, gas-rich low surface brightness galaxy in the Dorado group, at a distance of 17.7 Mpc. Combining deep MeerKAT 21-cm observations from the MeerKAT Hi Observations of Nearby Galactic Objects: Observing Southern Emitters (MHONGOOSE) survey with deep photometric images from the VST Early-type Galaxy Survey (VEGAS) we find a stellar and neutral atomic hydrogen (H i) gas mass of M∗ = 2:23 × 106M⊙ and MHI = 1:68 × 106 M⊙, respectively. This low surface brightness galaxy is the lowest-mass Hi detection found in a group beyond the local Universe (D ≳ 10 Mpc). The dwarf galaxy has the typical overall properties of gas-rich low surface brightness galaxies in the Local group, but with some striking differences. Namely, the MHONGOOSE observations reveal a very low column density (∼ 1018-19 cm-2) Hi disk with asymmetrical morphology possibly supported by rotation and higher velocity dispersion in the centre. There, deep optical photometry and UV observations suggest a recent enhancement of the star formation. Found at galactocentric distances where in the Local Group dwarf galaxies are depleted of cold gas (at a projected distance of 390 kpc from the group centre), this galaxy is likely on its first orbit within the Dorado group. We discuss the possible environmental effects that may have caused the formation of the Hi disk and the enhancement of star formation (SF), highlighting the short-lived phase (a few hundreds million years) of the gaseous disk, before either SF or hydrodynamical forces will deplete the gas of the galaxy.
Keywords
galaxies: dwarf, galaxies: evolution, galaxies: formation, galaxies: kinematics and dynamics
Publication Title
Astronomy and Astrophysics
Grant
882793
Rights
© The Authors 2024. This is an Open Access work distributed under the terms of the Creative Commons Attribution Licence (http://creativecommons.org/licenses/by/4.0/) which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.
Recommended Citation
MHONGOOSE: A MeerKAT nearby galaxy H I survey W. J. G. de Blok, J. Healy, F. M. Maccagni, D. J. Pisano, A. Bosma, J. English, T. Jarrett, A. Marasco, G. R. Meurer, S. Veronese, F. Bigiel, L. Chemin, F. Fraternali, B. W. Holwerda, P. Kamphuis, H. R. Klöckner, D. Kleiner, A. K. Leroy, M. Mogotsi, K. A. Oman, E. Schinnerer, L. Verdes-Montenegro, T. Westmeier, O. I. Wong, N. Zabel, P. Amram, C. Carignan, F. Combes, E. Brinks, R. J. Dettmar, B. K. Gibson, G. I. G. Jozsa, B. S. Koribalski, S. S. McGaugh, T. A. Oosterloo, K. Spekkens, A. C. Schröder, E. A. K. Adams, E. Athanassoula, M. A. Bershady, R. J. Beswick, S. Blyth, E. C. Elson, B. S. Frank, G. Heald, P. A. Henning, S. Kurapati, S. I. Loubser, D. Lucero, M. Meyer, B. Namumba, S.-H. Oh, A. Sardone, K. Sheth, M. W. L. Smith, A. Sorgho, F. Walter, T. Williams, P. A. Woudt and A. Zijlstra A&A, 688 (2024) A109 DOI: https://doi.org/10.1051/0004-6361/202348297
Manuscript Version
Final Publisher Version