Discovery of a Rare Group of Dwarf Galaxies in the Local Universe

Fuente: arXiv
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Main Authors: Paudel, Sanjaya, Sabiu, Cristiano G., Yoon, Suk-Jin, Duc, Pierre-Alain, Yoo, Jaewon, Müller, Oliver
Format: Preprint
Published: 2024
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author Paudel, Sanjaya
Sabiu, Cristiano G.
Yoon, Suk-Jin
Duc, Pierre-Alain
Yoo, Jaewon
Müller, Oliver
author_facet Paudel, Sanjaya
Sabiu, Cristiano G.
Yoon, Suk-Jin
Duc, Pierre-Alain
Yoo, Jaewon
Müller, Oliver
contents 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 $\times$ 10$^{7}$ M$_{\odot}$. The derived total dynamical mass of the group is $M_{\rm dyn}$ = 6.02$\times$10$^{10}$ M$_{\odot}$, whereas its total baryonic mass (stellar + HI) is 2.6$\times$10$^{9}$ 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.
format Preprint
id arxiv_https___arxiv_org_abs_2411_10045
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Discovery of a Rare Group of Dwarf Galaxies in the Local Universe
Paudel, Sanjaya
Sabiu, Cristiano G.
Yoon, Suk-Jin
Duc, Pierre-Alain
Yoo, Jaewon
Müller, Oliver
Astrophysics of Galaxies
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 $\times$ 10$^{7}$ M$_{\odot}$. The derived total dynamical mass of the group is $M_{\rm dyn}$ = 6.02$\times$10$^{10}$ M$_{\odot}$, whereas its total baryonic mass (stellar + HI) is 2.6$\times$10$^{9}$ 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.
title Discovery of a Rare Group of Dwarf Galaxies in the Local Universe
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2411.10045