Understanding the internal dynamics of elliptical galaxies without non-baryonic dark matter - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Monthly Notices of the Royal Astronomical Society Année : 2016

Understanding the internal dynamics of elliptical galaxies without non-baryonic dark matter

J. Dabringhausen
  • Fonction : Auteur
P. Kroupa
  • Fonction : Auteur
B. Famaey
M. Fellhauer
  • Fonction : Auteur

Résumé

Assuming virial equilibrium and Newtonian dynamics, low-mass early-type galaxies have larger velocity dispersions than expected from the amount of baryons they contain. The conventional interpretation of this finding is that their dynamics is dominated by non-baryonic matter. However, there is also strong evidence that many low-mass early-type galaxies formed as tidal dwarf galaxies, which would contain almost no dark matter. Using an extensive catalogue of early-type galaxies, we therefore discuss how the internal dynamics of early-type galaxies in general can be understood by replacing the assumption of non-baryonic dark matter with two alternative assumptions. The first assumption is that Milgromian dynamics (i.e. MOdified Newtonian Dynamics [MOND]) is valid, which changes the effective gravitational force in the weak-field limit. The second assumption is that binary stars affect the observed line-of-sight velocity dispersions. Some moderate discrepancies between observed and predicted velocity dispersions remain also when these effects are implemented. Nevertheless, the observed velocity dispersions in early-type galaxies can then easily be explained without invoking the presence of non-baryonic dark matter in them, but with already documented variations of the galaxy-wide stellar initial mass function and non-equilibrium dynamics in some of the low-mass early-type galaxies.
Fichier principal
Vignette du fichier
stw2001.pdf (1023.53 Ko) Télécharger le fichier
Origine : Fichiers produits par l'(les) auteur(s)

Dates et versions

hal-03146792 , version 1 (19-02-2021)

Identifiants

Citer

J. Dabringhausen, P. Kroupa, B. Famaey, M. Fellhauer. Understanding the internal dynamics of elliptical galaxies without non-baryonic dark matter. Monthly Notices of the Royal Astronomical Society, 2016, 463 (2), pp.1865-1880. ⟨10.1093/mnras/stw2001⟩. ⟨hal-03146792⟩
79 Consultations
62 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More