Related papers: Theoretical stellar models for old galactic cluste…
In integrated-light, some color-color diagrams that use optical and near-infrared photometry show surprisingly orthogonal grids as age and metallicity are varied, and they are coming into common usage for estimating the average age and…
We compare the observed colour-magnitude diagrams (CMD) and the main sequence luminosity functions (LFs) of four Large Magellanic Cloud (LMC) star clusters namely, NGC 1711, NGC 2004, NGC 2164 and NGC 2214 with the synthetic ones derived…
We make use of the Next Generation model atmospheres by Allard et al. (1997) and Hauschildt, Allard & Baron (1999) to compute theoretical models for low and very low-mass stars for selected metallicities in the range Z= 0.0002 to 0.002. On…
We derive photometric, structural and dynamical evolution-related parameters of 11 nearby open clusters with ages in the range 70 Myr to 7 Gyr and masses in the range $\approx400$ \ms to $\approx5 300$ \ms. We search for relations of…
The large majority of extragalactic star cluster studies performed to date essentially use multi-colour photometry, combined with theoretical stellar synthesis models, to derive ages, masses, extinction estimates, and metallicities. M31…
Visual and near-infrared colours are used to identify intermediate-age globular cluster in early-type galaxies. In NGC5846 and NGC4365 colour-colour diagrams (V-I vs. V-K) reveal a sub-population in the globular cluster systems with an age…
Several population synthesis models now predict integrated colors of simple stellar populations in the mid-infrared bands. To date, the models have not been extensively tested in this wavelength range. In a comparison of the predictions of…
Abell 1767 is a dynamically relaxed, cD cluster of galaxies with a redshift of 0.0703. Among 250 spectroscopically confirmed member galaxies within a projected radius of 2.5r_{200}, 243 galaxies (~ 97%) are spectroscopically covered by the…
The Hydra I cluster offers an excellent opportunity to study and compare the relic old stellar populations in the core of its two brightest galaxies. In addition, the differing kinematics of the two galaxies allows a test of the local…
We investigate the long-term dynamical evolution of two distinct stellar populations of low-mass stars in globular clusters in order to study whether the energy equipartition process can explain the high number of stars harbouring abundance…
We consider tidal masses and ages of Milky Way open clusters, as well as a simple model of their distribution. Our aim is to investigate the space of model parameters and the correspondence between modelled and observed two-dimensional…
Central velocity dispersions and eight line-strength Lick indices have been determined from 1.3${\rm \AA}$ resolution long-slit spectra of 16 elliptical galaxies in Hickson compact groups. These data were used to determine galaxy properties…
High spectral resolution evolutionary synthesis models have become a routinely used ingredient in extragalactic work, and as such deserve thorough testing. Star clusters are ideal laboratories for such tests. This paper applies the spectral…
The number of known globular clusters in the Galactic bulge has been increasing steadily thanks to different new surveys. The aim of this study is to provide a census of the newly revealed globular clusters in the Galactic bulge, and…
We study the stellar population of galaxies with active star formation, determining ages of the stellar components by means of spectral population synthesis of their absorption spectra. The data consist of optical spectra of 185 nearby ($z…
We develop a new set of models for intermediate-metallicity single stellar populations in the blue/optical region and use those models to determine the spectroscopic age of 47 Tuc. The models are based on a moderately high-resolution (1.8 A…
[Abridged] We present a large, new set of stellar evolution models and isochrones for an alpha-enhanced metal distribution typical of Galactic halo and bulge stars; it represents a homogeneous extension of our stellar model library for a…
We investigate in detail the white dwarf cooling sequence of the globular cluster Messier 4. In particular we study the influence of various systematic uncertainties, both observational and theoretical, on the determination of the cluster…
(ABRIDGED) We assess the systematic uncertainties in (young) cluster age, mass, and - to a lesser extent - extinction and metallicity determinations, based on broad-band imaging observations with the Hubble Space Telescope. Our aim here is…
We determine the age and mass of the three best solar twin candidates in open cluster M67 through lithium evolutionary models. We computed a grid of evolutionary models with non-standard mixing at metallicity [Fe/H] = 0.01 with the…