

We study the dynamical models of two massive nearby early-type galaxies, NGC 4473 and NGC 4697, using globular clusters (GCs) as tracers of their gravitational potential. We use their velocity dispersion to model their dynamics based on solving the spherical Jeans equation in both Newtonian and MOdified Newtonian Dynamics (MOND) approaches. We take into account the orbital anisotropies and we model the following three cases: we study isotropic, tangentially and radially anisotropic models interior to ∼12 effective radii for NGC 4473 and interior to ∼3 effective radii for NGC 4697. We analyse these two galaxies that are part of the larger SLUGGS sample because we obtained photometric data using the new 1.40 m telescope 'Milanković' for both objects to estimate the contribution of the visible, stellar, component, using several stellar population synthesis models as priors. In addition to three widely analysed MOND models (standard, simple, and toy) for the first time in the literature we analyse the Zhao MOND model on elliptical galaxies. We also analysed several additional MOND models found in the literature and we also tested the Einasto dark matter models. We find that in the Newtonian approach, both galaxies in general may need dark matter to describe their kinematics. The best-fitting results were in both cases obtained with the inclusion of the dark matter halo but we managed to find solutions for which the dark component is not needed. We also find that both galaxies may be well modelled using all the tested MOND functions assuming the existence of the visible matter only. © 2018 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society.
| Engineering controlled terms: | AnisotropyDynamicsKinematicsPopulation statisticsStars |
|---|---|
| Engineering uncontrolled terms | Dark matterEffective radiusElliptical galaxiesGalaxies: elliptical and lenticularGalaxies: individualsGalaxies: Kinematics and dynamicsGalaxies:structureGalaxy: individual (NGC 4473, NGC 4697)Newtonian dynamicsNewtonians |
| Engineering main heading: | Galaxies |
| Funding sponsor | Funding number | Acronym |
|---|---|---|
| National Science Foundation See opportunities by NSF | NSF | |
| European Commission See opportunities by EC | 256772 | EC |
| European Commission See opportunities by EC | EC | |
| Ministarstvo Prosvete, Nauke i Tehnološkog Razvoja | 176021 | MPNTR |
| Ministarstvo Prosvete, Nauke i Tehnološkog Razvoja | MPNTR |
The authors gratefully acknowledge the valuable comments of the referee that helped to significantly improve the quality of the manuscript. We acknowledge the support from the Ministry of Education, Science and Technological Development of the Republic of Serbia (MESTDRS) through project no. 176021 ‘Visible and Invisible Matter in Nearby Galaxies: Theory and Observations’. This research used the NASA/IPAC Extragalactic Database, which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. We acknowledge the usage of the HyperLeda data base (http://leda.univ-lyon1.fr). This research has used the VizieR catalogue access tool, CDS, Strasbourg, France. The original description of the VizieR service was published in A&AS 143, 23. We thank the technical operators at the Astronomical Station Vidojevica (ASV), Miodrag Sekulić and Petar Kostić for their excellent work. We acknowledge numerous useful discussions with Dr. Michal Bílek. We acknowledge the financial support by the European Commission through project BELISSIMA (BELgrade Initiative for Space Science, Instrumentation and Modelling in Astrophysics, call FP7-REGPOT-2010-5, contract No. 256772) which was used to procure the ‘Milanković’ 1.40 m telescope with the support from the MESTDRS. We thank the MESTDRS for the continued support of the ASV.
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