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Current instruments and spectral analysis programs are now able to decompose the integrated spectrum of a stellar system into distributions of ages and metallicities. The reliability of these methods have rarely been tested on nearby…
Various methods for age dating globular clusters in ellipticals are presented. We first present spectroscopy of individual globular clusters (feasible with the advent of the 10m-class telescopes), and the measurement of Balmer line indices.…
This paper is the second of a series that investigates the stochasticity and degeneracy problems that hinder the derivation of the age, mass, extinction, and metallicity of unresolved star clusters in external galaxies when broad-band…
We have acquired intermediate resolution spectra in the 3700-7000 A wavelength range for a sample of 65 early-type galaxies predominantly located in low density environments, a large fraction of which show emission lines. The spectral…
Stellar spectra derived from current multiple-object fiber-fed spectroscopic radial-velocity surveys, of the type feasible with, among other examples, AUTOFIB, 2dF, HYDRA, NESSIE, and the Sloan survey, differ significantly from those…
The aim of this article is to demonstrate the useful role that can be played by spectropolarimetric observations of young and evolved emission line stars that analyse the linearly polarized component in their spectra. At the time of…
We present a new model for computing the spectral evolution of stellar populations at ages between 100,000 yr and 20 Gyr at a resolution of 3 A across the whole wavelength range from 3200 to 9500 A for a wide range of metallicities. These…
We present a cautionary study exploring the reliability of the H-delta line in the integrated spectra of galaxies for determining galaxy ages. Our database consists of the observed integrated spectra of ~120 early-type galaxies, of 7…
The upcoming generation of optical spectrographs on four meter-class telescopes, with their huge multiplexing capabilities, excellent spectral resolution, and unprecedented wavelength coverage, will provide high-quality spectra for…
We built modelled spectra of stellar population at high resolution and with variable alpha-elements enhancements. Analysing spectra of Galactic globular clusters we show that it is possible to derive reliably and efficiently [Mg/Fe] using…
In this third paper of a series on the precision of obtaining ages of stellar populations using the full spectrum fitting technique, we examine the precision of this technique in deriving possible age spreads within a star cluster. We test…
Context. Stochasticity and physical parameter degeneracy problems complicate the derivation of the parameters (age, mass, and extinction) of unresolved star clusters when using broad-band photometry. Aims. We develop a method to simulate…
Using data from the WISE mission, we have measured near infra-red (NIR) photometry of a diverse sample of dust-free stellar systems (globular clusters, dwarf and giant early-type galaxies) which have metallicities that span the range -2.2 <…
We present a Bayesian method to determine simultaneously the age, metallicity, distance modulus, and interstellar reddening by dust of any resolved stellar population, by comparing the observed and synthetic color magnitude diagrams on a…
Stellar masses play a crucial role in the exploration of galaxy properties and the evolution of the galaxy population. In this paper, we explore the minimum possible uncertainties in stellar mass-to-light (M/L) ratios from the assumed star…
We have developed a method for fast and accurate stellar population parameters determination in order to apply it to high resolution galaxy spectra. The method is based on an optimization technique that combines active learning with an…
The efficient use of near-IR data in studies of external stellar populations depends on our ability to recognize the nature of the predominant sources of light, and to interprete these findings in terms of age and metallicity. Here we focus…
The pixel-to-pixel spectral fitting technique is often used in studies of stellar populations. It enables the user to infer several parameters from integrated light spectra such as ages and chemical abundances. In this paper, we examine the…
Integrated spectroscopy is the method of choice for deriving the ages of unresolved stellar systems. However, hot stellar evolutionary stages, such as hot horizontal branch stars and blue straggler stars (BSSs), can affect the integrated…
A new generation of spectral synthesis models has been developed in the recent years, but there is no matching -- in terms of quality and resolution -- set of template galaxy spectra for testing and refining the new models. Our main goal is…