doiSerbia

Low dark matter content of the nearby early-type galaxy NGC 821

Samurović S. (Astronomical observatory, Belgrade)
Vudragović A. (Astronomical observatory, Belgrade)
Jovanović M. (Astronomical observatory, Belgrade)
Ćirković M.M. (Astronomical observatory, Belgrade)

In this paper we analyze the kinematics and dynamics of the nearby early-type galaxy NGC 821 based on its globular clusters (GCs) and planetary nebulae (PNe). We use PNe and GCs to extract the kinematics of NGC 821 which is then used for the dynamical modelling based on the Jeans equation. We apply the Jeans equation using the Newtonian mass-follows-light approach assuming constant mass-to-light ratio and find that using such an approach we can successfully fit the kinematic data. The inferred constant mass-to-light ratio, 4:2 < M=LB < 12:4 present throughout the whole galaxy, implies the lack of significant amount of dark matter. We also used three different MOND approaches and found that we can fit the kinematic data without the need for additional, dark, component.

Keywords: dark matter, galaxies: elliptical and lenticular, galaxies: kinematics and dynamics, galaxies: structure

Projekat Ministarstva nauke Republike Srbije, br. 176021: Visible and invisible matter in nearby galaxies: theory and observations