Dynamical models of two lenticular galaxies: NGC 1023 and NGC 4526

Abstract

We study kinematics and dynamics of two lenticular galaxies that possess globular clusters (GCs) which extend beyond approximately seven effective radii. We analyze two nearby lenticular galaxies, NGC 1023 and NGC 4526, based on their GCs. We extract the kinematics of these galaxies and use it for dynamical modeling based on the Jeans equation. The Jeans equation was solved in both the Newtonian mass-follows-light approach assuming constant mass-to-light ratio and assuming a dark halo in the Navarro-Frenk-White form. We find that while the first galaxy, NGC 1023, does not need a significant amount of dark matter, in the other galaxy, NGC 4526, the dark component fully dominates stellar matter in the total dynamical mass. In this paper we also used three different MOND approaches and found that while for both galaxies MOND models can provide successful fits of the observed velocity dispersion, in the case of NGC 4526 we have a hint of an additional dark component even in the MOND framework.