KDG 64: a large dwarf spheroidal or a small ultradiffuse satellite of Messier 81 - AstroParticule et Cosmologie Accéder directement au contenu
Article Dans Une Revue Monthly Notices of the Royal Astronomical Society Année : 2023

KDG 64: a large dwarf spheroidal or a small ultradiffuse satellite of Messier 81

Anton V Afanasiev
Igor V Chilingarian
  • Fonction : Auteur
Dmitry Makarov
  • Fonction : Auteur
Lidia Makarova
  • Fonction : Auteur
Daniel Fabricant
  • Fonction : Auteur
Nelson Caldwell
  • Fonction : Auteur
Sean Moran
  • Fonction : Auteur

Résumé

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.

Dates et versions

hal-04035050 , version 1 (17-03-2023)

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Citer

Anton V Afanasiev, Igor V Chilingarian, Kirill A Grishin, Dmitry Makarov, Lidia Makarova, et al.. KDG 64: a large dwarf spheroidal or a small ultradiffuse satellite of Messier 81. Monthly Notices of the Royal Astronomical Society, 2023, 520 (4), pp.6312-6321. ⟨10.1093/mnras/stad559⟩. ⟨hal-04035050⟩
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