Modelling galactic spectra - I. A dynamical model for NGC 3258

Author(s)
Veronique de Bruyne, Sven de Rijcke, Herwig B. Dejonghe, Werner Zeilinger
Abstract

We present a method to analyse absorption-line spectra of a galaxy designed to determine the stellar dynamics and the stellar populations by a direct fit to the spectra. This paper is the first to report on the application of the method to data. The modelling results in the knowledge of distribution functions that are sums of basis functions. The practical implementation of the method is discussed and a new type of basis function is introduced. With this method, a dynamical model for NGC 3258 is constructed. This galaxy can be modelled successfully with a potential containing 30 per cent dark matter within lr e with a mass of 1.6 × 1011 M?. The total mass within 2re is estimated as 5 × 1011 M?, containing 63 per cent dark matter. The model is isotropic in the centre, is radially anisotropic between 0.2 and 2 kpc (0.88re), and becomes tangentially anisotropic further on. The photometry reveals the presence of a dust disc near the centre.

Organisation(s)
Department of Astrophysics
External organisation(s)
Ghent University
Journal
Monthly Notices of the Royal Astronomical Society
Volume
349
Pages
440-460
No. of pages
21
ISSN
0035-8711
Publication date
2004
Peer reviewed
Yes
Austrian Fields of Science 2012
103003 Astronomy
Portal url
https://ucrisportal.univie.ac.at/en/publications/2dd6ea1c-8c5e-47d6-ae4f-622563225561