Related papers: A Photometric System for Metallicity Mapping in Ga…
Assuming that in the atmospheres of low-mass, metal-poor red giant stars, 1-D models based on LTE accurately predict the abundance of iron from Fe II, we derive a globular cluster metallicity scale based on the equivalent widths of Fe II…
Asteroseismology has the capability of delivering stellar properties which would otherwise be inaccessible, such as radii, masses and thus ages of stars. When coupling this information with classical determinations of stellar parameters,…
We present the mass-metallicity (MZ) and luminosity-metallicity (LZ) relations at z ~ 0.8 from ~1350 galaxies in the Deep Extragalactic Evolutionary Probe 2 (DEEP2) survey. We determine stellar masses by fitting the spectral energy…
We present near-infrared integral field spectroscopy of ten Herschel selected galaxies at z~1.5. From detailed mapping of the H$\alpha$ and [NII] emission lines we trace the dynamics, star formation rates, metallicities and also investigate…
The different regimes of gravitational lensing constitutes an interesting tool in order to map the mass distribution in galaxy clusters on different scales. In this proceedings article, I review some work I have performed on this topic.…
Our unified chemical and spectrophotometric evolution code allows to simultaneously study the ISM abundances of a series of elements and the spectral properties of the stellar population in our model galaxies. We use stellar evolutionary…
Very metal-poor massive stars in the Local Group are our best proxies for the Universe's first stars, making them essential for modeling reionization and early galactic chemical evolution. Studying such stars in our Local Universe is key to…
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…
We demonstrate a significant (> 5-sigma) correlation between the mean color of metal-poor globular cluster (GC) systems and parent galaxy luminosity. A Bayesian Markov Chain Monte Carlo method is introduced to find the mean color, and is…
We obtained high resolution ELODIE and CORALIE spectra for both components of 20 wide visual binaries composed of an F-, G- or K-dwarf primary and an M-dwarf secondary. We analyse the well understood spectra of the primaries to determine…
In this investigation, we present an analysis of the metallicity distribution that pertains to neutral gas in the local Galactic interstellar medium (ISM). We derive relative ISM metallicities for a sample of 84 sight lines probing diffuse…
The metallicity spread, or the metallicity trend along the evolutionary sequence of a globular cluster, is a rich source of information to help understand the cluster physics (e.g. multiple populations) and stellar physics (e.g. atomic…
We present new empirical and theoretical calibrations of two photometric metallicity indices based on Walraven photometry. The empirical calibration relies on a sample of 48 Cepheids for which iron abundances based on high resolution…
We review several aspects of clusters of galaxies and their application to cosmology. We present first results of numerical simulations of the dynamics of the intra-cluster gas and of different interaction processes between cluster galaxies…
Preliminary results based on a large compilation of line-strength profiles are presented and discussed. Elliptical galaxies (Es) with strong central Mg$_2$ show steeper line-strength gradients. These galaxies are more massive and have…
We perform integrated spectroscopy of 24 Galactic globular clusters. Spectra are observed from one core radius for each cluster with a high wavelength resolution of ~2.0 A FWHM. In combination with two existing data sets from Puzia et al.…
We present the results of a study utilising ultra-deep, rest-frame UV, spectroscopy to quantify the relationship between stellar mass and stellar metallicity for 681 star-forming galaxies at $2.5<z<5.0$ ($\langle z \rangle = 3.5 \pm 0.6$)…
We use detailed modeling of stellar populations of nearby galaxies to calculate population parameters. Our sample of galaxies includes most galaxies of the Local Group and several more distant giant galaxies. Available data are sufficient…
We address the problem of deriving, from the observed projected metallicity gradients, the intrinsic metallicity distribution of elliptical galaxies as a function of their integrals of motion. The method is illustrated by an application to…
Stellar ages are an important parameter to study the chemical evolution of the Galaxy. In recent years, several studies have established the existence of a relationship between chemical clocks and stellar ages. The [Y/Mg] clock is a…