Related papers: Abundance Ratios in Early-Type Galaxies
We report the abundances of 30 elements in 23 metal-poor ([Fe/H] <-1.7) giants. These are based on 7774 equivalent widths and spectral synthesis of 229 additional lines. Hyperfine splitting is taken into account when appropriate. Our choice…
Isotope ratios have opened a new window into the study of the details of stellar evolution, supernovae, and galactic chemical evolution. We present the evolution of the isotope ratios of elemental abundances (from C to Zn) in the solar…
We present results of a detailed chemical analysis performed on 23 main-sequence turnoff stars having -3.4<=[Fe/H]<=-2.2, a sample selected to be highly homogeneous in T_eff and log(g). We investigate the efficiency of mixing in the early…
We use our new stellar population models, which include effects from variable element abundance ratios, to model the Ca4227 absorption line indices of early-type galaxies (Trager et al.), and to derive calcium element abundances. We find…
We present abundance ratios for 23 elements with respect to Fe in a sample of stars with a wide range in luminosity, from luminous giants to stars near the turnoff, in the globular cluster M71. The analyzed spectra, obtained with HIRES at…
ABRIDGED: To compare the chemistries of stars in the Milky Way dSph galaxies with stars in the Galaxy, we have compiled a large sample of Galactic stellar abundances from the literature. As found in previous studies, the [alpha/Fe] ratios…
Abundances of alpha-elements such as Ca and Mg in disk and halo stars are usually derived from equivalent widths lines measured on high resolution spectra, and assuming Local Thermodynamic Equilibrium (LTE) . In this paper, we present…
We numerically investigate abundance properties of the Galactic globular clusters (GCs) by adopting a new ``external pollution'' scenario. In this framework, GCs are assumed to originate in forming low-mass dwarfs embedded in dark matter…
We derive the abundance of 19 elements in a sample of 64 stars with fundamental parameters very similar to solar, which minimizes the impact of systematic errors in our spectroscopic 1D-LTE differential analysis, using high-resolution…
The spatial distribution of elemental abundances in the disc of our Galaxy gives insights both on its assembly process and subsequent evolution, and on the stellar nucleogenesis of the different elements. Gradients can be traced using…
High quality X-ray spectra of NGC 4636 are obtained with ASCA. Theoretical models are found unable to reproduce the data in the Fe-L line region. Spectral data above 1.4 keV indicate that Mg to Si abundance ratio is $\sim 1$ solar. Assuming…
The chemical compositions of the stars in Milky Way (MW) satellite galaxies reveals the history of gas flows and star formation (SF) intensity. This talk presented a Keck/DEIMOS spectroscopic survey of the Fe, Mg, Si, Ca, and Ti abundances…
Metal-poor stars provide the fossil record of Galactic chemical evolution and the nucleosynthesis processes that took place at the earliest times in the history of our Galaxy. From detailed abundance studies of low mass, extremely…
We investigate sulphur abundance in 74 Galactic stars by using high resolution spectra obtained at ESO VLT and NTT telescopes. For the first time the abundances are derived, where possible, from three optical multiplets: Mult. 1, 6, and 8.…
The aim of this paper is to provide the fundamental parameters and abundances for a large sample of local clump giants with a high accuracy. The selection of clump stars for the sample group was made applying a color - absolute magnitude…
While we observe a large amount of cold interstellar gas and dust in a subset of the early-type galaxy (ETG) population, the source of this material remains unclear. The two main, competing scenarios are external accretion of lower mass,…
Recent improvements in the age dating of stellar populations and single stars allow us to study the ages and abundance of stars and galaxies with unprecedented accuracy. We here compare the relation between age and \alpha-element abundances…
Due to their different nucleosynthetic origin, a stellar population produces oxygen (O) and iron (Fe) on different timescales and their relative abundance can deviate strongly from solar. Galaxy formation models should treat these elements…
The stellar populations of galaxies hold vital clues to their formation histories. In this paper we present results based on modeling stacked spectra of early-type galaxies drawn from the Sloan Digital Sky Survey (SDSS) as a function of…
Stellar chemical element ratios have well-defined systematic trends as a function of abundance, with an excellent correlation of these trends with stellar populations defined kinematically. This is remarkable, and has significant…