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Related papers: Integrated Spectroscopy of Bulge Globular Clusters…

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We present simple stellar population (SSP) models with scaled-solar and alpha-element enhanced abundances. The SSP models are based on the Dartmouth Stellar Evolution Database, our library of synthetic stellar spectra, and a detailed…

Astrophysics of Galaxies · Physics 2015-05-13 Hyun-chul Lee , Guy Worthey , Aaron Dotter

We present a comprehensive spectroscopic study of the integrated light of metal-rich Galactic globular clusters and the stellar population in the Galactic bulge. We measure line indices which are defined by the Lick standard system and…

All 25 Lick/IDS spectral indices have been computed for the integrated light of simple stellar populations over broad ranges of age and metallicity and with effects from horizontal-branch stars fully implemented. For Balmer indices a…

Astrophysics · Physics 2009-11-11 Hyun-chul Lee , Guy Worthey

To provide an empirical calibration relation in order to convert Lick indices into abundances for the integrated light of old, simple stellar populations for a large range in the observed [Fe/H] and [alpha/Fe]. This calibration supersedes…

Astrophysics of Galaxies · Physics 2015-05-27 A. Pipino , I. J. Danziger

We provide the whole set of Lick indices from CN1 to TiO2 of Simple Stellar Population models with, for the first time, variable element abundance ratios, [alpha/Fe]=0.0, 0.3, 0.5, [alpha/Ca]=-0.1, 0.0, 0.2, 0.5, and [alpha/N]=-0.5, 0.0.…

Astrophysics · Physics 2009-11-07 Daniel Thomas , Claudia Maraston , Ralf Bender

We compute new population synthesis models of Lick absorption line indices with variable alpha/Fe ratios and use them to derive average ages, metallicities, and alpha/Fe element enhancements for a sample of 126 field and cluster early-type…

Astrophysics · Physics 2007-05-23 Daniel Thomas , Claudia Maraston , Ralf Bender

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

We present high S/N integrated spectra of 24 star clusters in the LMC obtained using the FLAIR spectrograph at the UK Schmidt. The spectra have been placed onto the Lick/IDS system in order to test the calibration of Simple Stellar…

Astrophysics · Physics 2009-11-07 Michael A. Beasley , Fiona Hoyle , Ray M. Sharples

Spectroscopic studies of elliptical galaxies show that their stellar population ages, mean metallicity, and $\alpha$-enhancement traced by [Mg/Fe] all increase with galaxy stellar mass or velocity dispersion. We use one-zone galactic…

Comparing models of Simple Stellar Populations (SSP) with observed line strengths generally provides a tool to break the age-metallicity degeneracy in elliptical galaxies. Due to the wide range of Balmer line strengths observed, ellipticals…

Astrophysics · Physics 2009-12-08 Claudia Maraston , Daniel Thomas

The radial profiles of the Hb, Mg, and Fe line-strength indices are presented for a sample of eight spiral galaxies with a low surface-brightness stellar disc and a bulge. The correlations between the central values of the line-strength…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 L. Morelli , E. M. Corsini , A. Pizzella , E. Dalla Bontà , L. Coccato , J. Méndez-Abreu , M. Cesetti

An analysis of ages, metallicities, and [alpha/Fe] ratios of globular cluster systems in early-type galaxies is presented, based on Lick index measurements summarized in Puzia et al. (2004, Paper I of this series). In the light of…

We complement our study of alpha/Fe enhanced stellar population models of Lick absorption indices (Thomas et al. 2003) by comparing two sets of alpha/Fe enhanced models. In both models the impact on Lick indices due to alpha/Fe enhancement…

Astrophysics · Physics 2009-11-07 Daniel Thomas , Claudia Maraston

We present models that predict spectra of old- and intermediate-aged stellar populations at 2.51\AA\ (FWHM) with varying [\alpha/Fe] abundance. The models are based on the MILES library and on corrections from theoretical stellar spectra.…

We derive central values and logarithmic gradients for the Hbeta, Mg and Fe indices of 35 early-type galaxies in the Coma cluster. We find that pure elliptical galaxies have on average slightly higher velocity dispersions, lower Hbeta, and…

Astrophysics · Physics 2008-11-26 D. Mehlert , D. Thomas , R. P. Saglia , R. Bender , G. Wegner

The leading method for the determination of relevant stellar population parameters of unresolved extragalactic Globular Clusters is through the study of their integrated spectroscopy, where Balmer line-strength indices are considered to be…

Optical integrated spectra of bulges have been obtained for 28 spiral galaxies. By applying an appropriate aperture size for each galaxy, the unavoidable contamination of disk starlight has been carefully minimized and set to $\sim$ 1/7 of…

Astrophysics · Physics 2009-10-28 P. Jablonka , P. Martin , N. Arimoto

It is widely accepted that individual Galactic globular clusters harbor two coeval generations of stars, the first one born with the `standard' alpha-enhanced metal mixture observed in field Halo objects, the second one characterized by an…

Astrophysics of Galaxies · Physics 2012-03-21 Paula Coelho , Susan Percival , Maurizio Salaris

We present single stellar population (SSP) equivalent ages, metallicities, and abundance ratios for local elliptical galaxies derived from Hbeta, Mgb, and <Fe> absorption line strengths. We use an extension of the Worthey (1994) stellar…

Astrophysics · Physics 2011-05-05 S. C. Trager , S. M. Faber , Guy Worthey , J. Jesus Gonzalez

We use our new, flux-calibrated stellar population model of absorption-line indices to derive ages, metallicities, and various element abundance ratios from integrated light spectroscopy of galactic globular clusters. The ages agree well…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Daniel Thomas , Jonas Johansson , Claudia Maraston
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