Related papers: Age, metallicity and alpha-elements abundance in s…
We use our new, flux-calibrated stellar population model of absorption-line indices to derive ages, metallicities, and various element abundance ratios from integrated light spectroscopy of galactic globular clusters. The ages agree well…
We present differential stellar population models, which allow improved determinations of the ages, iron and alpha-element abundances of old stellar populations from spectral fitting. These new models are calibrated at solar abundances…
We have obtained [Mg/Fe] measurements for 76.3% of the stars in the MILES spectral library used for understanding stellar atmospheres and stellar populations in galaxies and star clusters. These abundance ratios were obtained through (1) a…
The age and chemical composition of the stars in present-day galaxies carry important clues about their star formation processes. The latest generation of population synthesis models have allowed to derive age and stellar metallicity…
It is currently impossible to determine the abundances and ages of the stellar populations of distant, dense stellar systems star by star. Therefore, methods to analyze the composite light of stellar systems are required. I review the…
We present updated stellar population models appropriate for old ages (>1 Gyr) and covering a wide range in metallicities (-1.5<[Fe/H]<0.3). These models predict the full spectral variation associated with individual element abundance…
Establishing the reliability with which stellar population parameters can be measured is vital to extragalactic astronomy. Galactic GCs provide an excellent medium in which to test the consistency of Single Stellar Population (SSP) models…
We compute new population synthesis models of Lick absorption line indices with variable alpha/Fe ratios and use them to derive average ages, metallicities, and alpha/Fe element enhancements for a sample of 126 field and cluster early-type…
We have obtained [Mg/Fe] for around 77% of the stars of the MILES library of stellar spectra in order to include this important information into simple stellar population (SSP) models. The abundance ratios, which were carefully calibrated…
We present model spectra of stellar populations with variable chemical composition. We derived the [alpha/Fe] abundance ratio of the stars of the most important libraries (ELODIE, CFLIB and MILES) using full spectrum fitting and we…
I briefly review what has been recently learned from determinations of mean stellar ages and abundances from integrated light studies of early-type galaxies, and discuss some new questions posed by recent data. A short discussion of…
In order to build more realistic single stellar population (SSP) models with variable alpha-enhancement, we have recently determined [Mg/Fe] in a uniform scale with a precision of about 0.1 dex for 752 stars in the MILES empirical library.…
We present the results of determination of the age, helium mass fraction (Y) in terms of the used stellar evolutionary models, metallicity ([Fe/H]), and abundances of the elements C, O, Na, Mg, Ca, Ti, Cr and Mn for 26 globular clusters of…
To analyse stellar populations in galaxies a widely used method is to apply theoretically derived responses of stellar spectra and line indices to element abundance variations, hereafter referred to as response functions. These are applied…
We present the first models allowing one to explore in a consistent way the influence of changes in the alpha-element-to-iron abundance ratio on the high-resolution spectral properties of evolving stellar populations. The models cover the…
We present photometry and long-slit spectroscopy for 12 S0 and spiral galaxies selected from the Catalogue of Isolated Galaxies. The structural parameters of the sample galaxies are derived from the Sloan Digital Sky Survey i-band images by…
We used integrated-light medium-resolution spectra of six Galactic globular clusters and model stellar atmospheres to carry out population synthesis and to derive chemical composition and age of the clusters. We used medium-resolution…
We present models that predict spectra of old- and intermediate-aged stellar populations at 2.51\AA\ (FWHM) with varying [\alpha/Fe] abundance. The models are based on the MILES library and on corrections from theoretical stellar spectra.…
We present a new technique to determine age and metallicity of old stellar populations (globular clusters and elliptical galaxies) using an iterative principal component analysis on narrow band (Str\"omgren) colors. Our technique is capable…
We take a closer look at our published results of determination of ages, metallicities, helium mass fractions and abundances of chemical elements in Galactic globular clusters in order to find possible signatures of the phenomenon of…