Modelling galactic spectra - II. Simultaneous study of stellar dynamics and stellar mix in NGC 3258

In this paper we adopt a method to analyse absorption-line spectra from elliptical galaxies that determines the dynamics of the galaxy and at the same time offers a way to study the stellar populations in that galaxy by a direct fit to the spectra. The result of the modelling is a distribution function for each stellar population that is considered in the fit. The method is described in detail in the accompanying paper. This paper reports on a dynamical stellar population study in NGC 3258, based on spectra in two different wavelength regions, the near-infrared Ca II triplet around 8600 Angstrom and the Ca H and K lines around 3900 Angstrom. These absorption lines have discriminating power towards various stellar types. The dynamical model shows an increase in dwarfs (represented by G2V stars) towards the centre. Most of the rotation in the model is delivered by the giants (represented by M1 III stars). Moreover, the different models that were considered indicate that establishing a potential for a galaxy is dependent on the wavelength range used for the modelling.