Related papers: No Heavy Element Dispersion in the Globular Cluste…
Clusters of galaxies as the largest clearly defined objects in our Universe are ideal laboratories to study the distribution of the most abundant chemical elements heavier than hydrogen and helium and the history of their production. The…
We perform a comparative study of the ex--situ second--parameter pair globular clusters (GCs) M30 and M92, having similar metallicities but different horizontal branch morphologies. We obtain the similar mean primordial carbon abundances…
We observed a sample of 90 red giant branch (RGB) stars in NGC 2808 using FLAMES/GIRAFFE and the high resolution grating with the set up HR21. These stars have previous accurate atmospheric parameters and abundances of light elements. We…
We present a multiple stellar population study of the metal-poor globular cluster (GC) M92 (NGC 6341), which is long known for the substantial metallicity dispersion, using our own photometric system. We find two groups with slightly…
To better characterize the abundance patterns produced by the r-process, we have derived new abundances or upper limits for the heavy elements zinc (Zn), yttrium (Y), lanthanum (La), europium (Eu), and lead (Pb). Our sample of 161…
We present the abundances analysis for a sample of 11 red giant branch stars in the metal-poor globular cluster NGC 6809 based on high-resolution spectra. Our main goals are to characterize its chemical composition and analyze this…
We have observed high-dispersion echelle spectra of red giant members in the five open clusters NGC 1342, NGC 1662, NGC 1912, NGC 2354 and NGC 2447 and determined their radial velocities and chemical compositions. These are the first…
The astrophysical origin of the rapid neutron-capture process (r-process), which produces about half of the elements heavier than iron, remains uncertain. The oldest, most metal-poor stars preserve the chemical signatures of early…
The properties of the relative abundances of rapid and slow neutron-capture elements are studied using a catalog containing spectroscopic abundance determinations for 14~elements produced in various nuclear-synthesis processes for 90~open…
The [Sr/Ba] and [Y/Ba] scatter observed in some galactic halo stars that are very metal-poor stars and in a few individual stars of the oldest known Milky Way globular cluster NGC 6522,have been interpreted as evidence of early enrichment…
We report the first high spectral resolution study of 17 M giants kinematically confirmed to lie within a few parsecs of the Galactic Center, using R=24,000 spectroscopy from Keck/NIRSPEC and a new linelist for the infrared K band. We…
We present initial results from a redshift survey carried out with the Low Resolution Imaging Spectrograph on the 10~m W. M. Keck Telescope in the Hubble Deep Field. In the redshift distribution of the 140 extragalactic objects in this…
We have used spectra obtained as part of the Science Verification program of the FLAMES multi-object spectrograph mounted on Kueyen (VLT-UT2) to perform an abundance analysis of stars along the giant branch (RGB) in the globular cluster NGC…
Globular clusters (GCs) are the oldest stellar systems in the Milky Way. Long time considered as simple stellar populations, nowadays we recognize their complex star formation history through precise abundance analysis of a variety of…
Chemical elements in the hot medium permeating early-type galaxies, groups, and clusters make them an excellent laboratory for studying metal enrichment and cycling processes in the largest scales of the universe. Here, we report the…
We have obtained high-res, high S/N ratio CCD echelle spectra of 10 bright red giants in 3 GCs (47Tuc, NGC6752 and NGC6397) roughly spanning the range of metallicities of the galactic GC system; they reveal no evidence of star to star…
We present a chemical composition analysis of 36 giants in the nearby mildy metal-poor (<[Fe/H]> = -1.18) "CN-bimodal" globular cluster M4. Confronted with a cluster that has large and variable interstellar extinction across the cluster…
The spectroscopic and photometric signals of the star-to-star abundance variations found in globular clusters seem to be correlated with global parameters like the cluster's metallicity, mass and age. Understanding this behaviour could…
We present an analysis of high dispersion spectra (R~40000) of three red clump stars in the old open cluster NGC 6819. The spectra were obtained with SARG, the high dispersion spectrograph of the Telescopio Nazionale Galileo. The spectra…
We report the abundance analysis of one red giant branch star in the metal-poor outer halo globular cluster NGC 5694. We obtain [Fe/H] = -1.93, based on the ionized lines, and our metallicity measurement is in good agreement with previous…