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We present new integrated light spectroscopy of globular clusters (GCs) in NGC 5128 in order to measure radial velocities and derive ages, metallicities, and alpha-element abundance ratios. Using Gemini-S 8-m/GMOS, we obtained spectroscopy…
High-resolution spectra of six core helium-burning `clump' stars and three giants in the open cluster M 67 have been obtained with the SOFIN spectrograph on the Nordic Optical Telescope to investigate abundances of up to 25 chemical…
We report results that show that the straightforwardly star cluster metallicities obtained from Str\"omgren $vby$ photometry is age-dependent and need to be corrected for further use. This outcome arises from the comparison of [Fe/H] values…
We present a quantitative spectral analysis of five very massive stars in the Arches cluster, located near the Galactic center, to determine stellar parameters, stellar wind properties and, most importantly, metallicity content. The…
We report on detailed abundances of giants in the Galactic bulge, measured with the HIRES echelle spectrograph on the 10-m Keck telescope. We also review other work on the bulge field population and globular clusters using Keck/HIRES. Our…
Observations of Young Star Cluster ({\bf YSC}) systems in interacting galaxies are reviewed with particular emphasis on their Luminosity Functions ({\bf LF}) and colour distributions. A few spectroscopic abundance measurements are…
Open clusters are key chemical and age tracers of Milky Way evolution. While open clusters provide significant constraints on galaxy evolution, their use has been limited due to discrepancies in measuring abundances from different studies.…
Context: The formation and evolution of disk galaxies are long standing questions in Astronomy. Understanding the properties of globular cluster systems can lead to important insights on the evolution of its host galaxy. Aims: We aim to…
Evolutionary models taking into account radiative accelerations, thermal diffusion, and gravitational settling for 28 elements, including all those contributing to OPAL stellar opacities, have been calculated for solar metallicity stars of…
We derive age constraints for 1639 red giants in the APOKASC sample for which seismic parameters from Kepler, as well as effective temperatures, metallicities and [alpha/Fe] values from APOGEE DR12 are available. We investigate the relation…
We report abundance analysis for 6 M giant members of the old open cluster NGC6791, based on infrared spectroscopy (1.5-1.8 micron) at R=25,000, using the NIRSPEC spectrograph at the Keck II telescope. We find the iron abundance <[Fe/H]>=…
In the era of large high-resolution spectroscopic surveys, high-quality spectra can contribute to our understanding of the Galactic chemical evolution, providing chemical abundances belonging to the different nucleosynthesis channels, and…
Context: Studies based on high-precision abundance determinations revealed that chemical patterns of solar twins are characterised by the correlation between the differential abundances relative to the Sun and the condensation temperatures…
Sun-like dwarf stars in the solar neighborhood reflect ages, an ``average'' chemical evolution, and departures from that average. We show the chemical, and kinematic properties of four groups of Sunlike dwarfs form a continuum related to…
(Abridged) We performed the spectroscopic observations of 11 confirmed GCs in M31 with the Xinglong 2.16m telescope and we mainly focus on the fits method and the metallicity gradient for the M31 GC sample. We analyzed and discussed more…
We present a Bayesian implementation of isochrone fitting in deriving stellar ages and masses, incorporating absolute K magnitude ($\rm M_K$) derived from 2MASS photometry and Gaia DR1 parallax and differentiation between initial bulk…
Chemical clocks offer a powerful tool for estimating stellar ages from spectroscopic surveys. We present a new detailed spectroscopic analysis of 68 Kepler red giant stars to provide a suite of high-precision abundances along with…
Large samples of globular clusters (GC) with precise multi-wavelength photometry are becoming increasingly available and can be used to constrain the formation history of galaxies. We present the results of an analysis of Milky Way (MW) and…
We explore the reliability and robustness in measuring the age, metallicity and mass of a sample of old Milky Way globular clusters (GCs) from their integrated light, setting the stage for using GCs as cosmic clocks at high redshift. We…
We derive ages, metallicities and [alpha/Fe] ratios from the integrated spectra of 23 globular clusters in M31, by employing multivariate fits to two stellar population models. In parallel we analyze spectra of 21 Galactic globular clusters…