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We present updated stellar population models appropriate for old ages (>1 Gyr) and covering a wide range in metallicities (-1.5<[Fe/H]<0.3). These models predict the full spectral variation associated with individual element abundance…

Astrophysics of Galaxies · Physics 2018-02-28 Charlie Conroy , Alexa Villaume , Pieter van Dokkum , Karin Lind

We study spectroscopically determined iron abundances of 642 solar-type stars to search for the signature of accreted iron-rich material. We find that the metallicity [Fe/H] of a subset of 466 main sequence stars, when plotted as a function…

Astrophysics · Physics 2009-10-31 N. Murray , B. Chaboyer , B. Hansen , P. Arras , B. Noyes

We present radial velocities, stellar parameters, and detailed abundances of 39 elements derived from high-resolution spectroscopic observations of red giant stars in the luminous, metal-poor globular cluster NGC 5824. We observe 26 stars…

Solar and Stellar Astrophysics · Physics 2015-12-02 Ian U. Roederer , Mario Mateo , John I. Bailey , Meghin Spencer , Jeffrey D. Crane , Stephen A. Shectman

We present observational estimates of DV(Bump-HB) in a sample of 28 Galactic Globular Clusters (GGCs) observed by HST. The photometric accuracy and the sizable number of stars measured in each cluster allowed us to single out the RGB Bump…

Astrophysics · Physics 2009-10-31 M. Zoccali , S. Cassisi , G. Piotto , G. Bono , M. Salaris

The observed characteristics of globular cluster (GC) systems, such as metallicity distributions, are commonly used to place constraints on galaxy formation models. However, obtaining reliable metallicity values is particularly difficult…

Astrophysics of Galaxies · Physics 2019-07-10 Alexa Villaume , Aaron J. Romanowsky , Jean Brodie , Jay Strader

The metallicity distribution function of globular clusters (GCs) in galaxies is a key to understanding galactic formation and evolution. The calcium II triplet (CaT) index has recently become a popular metal abundance indicator thanks to…

Astrophysics of Galaxies · Physics 2016-03-16 Chul Chung , Suk-Jin Yoon , Sang-Yoon Lee , Young-Wook Lee

Globular clusters (GCs) are found ubiquitously in massive galaxies and due to their old ages, they are regarded as fossil records of galaxy evolution. Spectroscopic studies of GC systems are often limited to the outskirts of galaxies, where…

We present Hubble Space Telescope photometry in optical (F475X) and near-infrared (F110W) bands of the globular cluster (GC) systems of the inner halos of a sample of 15 massive elliptical galaxies. The targets are selected from the…

Astrophysics of Galaxies · Physics 2023-07-06 Kate Hartman , William E. Harris , John P. Blakeslee , Chung-Pei Ma , Jenny E. Greene

Star clusters are known to have smaller intrinsic metallicity spreads than dwarf galaxies due to their shorter star formation timescales. Here we use individual spectroscopic [Fe/H] measurements of stars in 19 Local Group dwarf galaxies, 13…

Astrophysics of Galaxies · Physics 2015-06-11 Ryan Leaman

The advent of the new class 8 meters telescopes allows for the first time the detailed study of numerous stars of galaxies other than our own. The Large Magellanic Cloud is one of the most interesting targets due to its proximity and its…

We present spectroscopic abundances and radial velocities for giant stars in the Galactic globular cluster omega Centauri based on the CaII infrared triplet. Two samples of stars were observed: 234 stars at M_V = 1.25 on the lower giant…

Astrophysics · Physics 2009-10-05 Nicholas B. Suntzeff , Robert P. Kraft

Establishing the reliability with which stellar population parameters can be measured is vital to extragalactic astronomy. Galactic GCs provide an excellent medium in which to test the consistency of Single Stellar Population (SSP) models…

Astrophysics · Physics 2008-11-26 Jon T. Mendel , Robert N. Proctor , Duncan A. Forbes

Stars in massive star clusters exhibit intrinsic variations in some light elements (MPs) that are difficult to explain in a coherent formation scenario. In recent years, HST photometry has led to the characterisation of the global…

Astrophysics of Galaxies · Physics 2022-06-29 Carmela Lardo , Maurizio Salaris , Santi Cassisi , Nate Bastian

It is well known that metal-poor red giant branch (RGB) stars show variations in some elemental abundances, including carbon, due to the internal mixing accompanied by their own in situ CN cycle in the hydrogen burning shell. With our new…

Astrophysics of Galaxies · Physics 2023-06-28 Jae-Woo Lee

We measure abundances of 12 elements (Na, Mg, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni) in a sample of 86 metal-poor ($-2 \lesssim \text{[Fe/H]} \lesssim -1$) subgiant stars in the solar neighborhood. Abundances are derived from…

Medium resolution (R=4,000 to 9,000) spectra of the near infrared Ca II lines (at 8498, 8542, and 8662 A) in M31 globular cluster integrated light spectra are presented. In individual stars the Ca II triplet (CaT) traces stellar…

Astrophysics of Galaxies · Physics 2015-12-23 Charli M. Sakari , George Wallerstein

We present high-quality, Keck spectroscopic data for a sample of 20 globular clusters (GCs) in the massive E0 galaxy NGC1407. A subset of twenty line-strength indices of the Lick/IDS system have been measured for both the GC system and the…

We present homogeneous and accurate iron abundances for 42 Galactic Cepheids based on high-spectral resolution (R~38,000) high signal-to-noise ratio (SNR>100) optical spectra collected with UVES at VLT (128 spectra). The above abundances…

We present a new homogeneous set of metallicity estimates based on Lick indices for 245 old globular clusters of the M31 galaxy comprised in the Revised Bologna Catalog. The metallicity distribution of the M31 globular clusters is briefly…

Solar and Stellar Astrophysics · Physics 2015-05-14 S. Galleti , M. Bellazzini , A. Buzzoni , L. Federici , F. Fusi Pecci

Most of the metals (elements heavier than helium) ever produced by stars in the member galaxies of galaxy clusters currently reside within the hot, X-ray emitting intra-cluster gas. Observations of X-ray line emission from this…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Norbert Werner , Ondrej Urban , Aurora Simionescu , Steven W. Allen
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