KDG 64: a large dwarf spheroidal or a small ultradiffuse satellite of Messier 81
| Autor: | Afanasiev, Anton V., Chilingarian, Igor V., Grishin, Kirill A., Makarov, Dmitry, Makarova, Lidia, Fabricant, Daniel, Caldwell, Nelson, Moran, Sean |
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| Rok vydání: | 2022 |
| Předmět: | |
| Zdroj: | Monthly Notices of the Royal Astronomical Society, Volume 520, Issue 4, pp.6312-6321, 2023 |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1093/mnras/stad559 |
| Popis: | Low-mass early-type galaxies, including dwarf spheroidals (dSph) and brighter dwarf ellipticals (dE), dominate the galaxy population in groups and clusters. Recently, an additional early-type population of more extended ultradiffuse galaxies (UDGs) has been identified, sparking a discussion on the potential morphological and evolutionary connections between the three classifications. Here, we present the first measurements of spatially resolved stellar kinematics from deep integrated-light spectra of KDG 64 (UGC 5442), a large dSph galaxy in the M 81 group. From these data, we infer stellar population properties and dark matter halo parameters using Jeans dynamical modelling. We find an old, metal-poor stellar population with no young stars and a dark matter mass fraction of ~ 90 per cent within the half-light radius. These properties and the position of KDG 64 on the Fundamental Plane indicate that it is a local analogue of smaller UDGs in the Coma and Virgo clusters and is probably a transitional dSph-UDG object. Its evolutionary path cannot be uniquely established from the existing data, but we argue that supernovae feedback and tidal heating played key roles in shaping KDG 64. Comment: 10 pages, 5 figures, published in MNRAS |
| Databáze: | arXiv |
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