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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 results of model atmosphere/line formation calculations which quantitatively test how the 21 classical and four higher-order Balmer-line Lick/IDS indices (Worthey et al. 1994; Worthey & Ottaviani 1997) depend on individual…

Astrophysics · Physics 2009-11-11 A. J. Korn , C. Maraston , D. Thomas

Basing on the huge library of 1-A resolution spectra calculated by Munari et al. over a large range of logT, log g, [Fe/H] and both for solar and a-enhanced abundance ratios [a/Fe], we present theoretical absorption-line indices on the Lick…

Astrophysics · Physics 2007-05-23 R. Tantalo , C. Chiosi , L. Piovan

Central velocity dispersions and eight line-strength Lick indices have been determined from 1.3${\rm \AA}$ resolution long-slit spectra of 16 elliptical galaxies in Hickson compact groups. These data were used to determine galaxy properties…

Astrophysics · Physics 2008-11-26 C. Mendes de Oliveira , P. Coelho , J. J. González , B. Barbuy

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 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 define a method for analysis of the integrated spectra of extra-galactic globular clusters that provides more reliable measures of age, metallicity and alpha-element abundance ratio than have so far been achieved. The method involves the…

Astrophysics · Physics 2009-11-10 Robert N. Proctor , Duncan A. Forbes , Michael A. Beasley

[Abridged] We present new model predictions for 16 Lick absorption line indices from Hdelta through Fe5335, and UBV colors for single stellar populations (SPs) with ages ranging between 1 and 15 Gyr, [Fe/H] ranging from -1.3 to +0.3, and…

Astrophysics · Physics 2009-11-11 Ricardo P. Schiavon

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 have computed the higher-order Balmer absorption line indices Hgamma and Hdelta (Worthey & Ottaviani 1997) for stellar population models with variable element ratios. The response of these indices to abundance ratio variations is taken…

Astrophysics · Physics 2009-11-10 Daniel Thomas , Claudia Maraston , Andreas Korn

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 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

We investigate the Mg-sigma and <Fe>-sigma relations in a sample of 72 early-type galaxies drawn mostly from cluster and group environments using a homogeneous data-set which is well-calibrated onto the Lick/IDS system. The small intrinsic…

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

We present line-strengths and kinematics from the central regions of 32 galaxies with Hubble types ranging from E to Sbc. Spectral indices, based on the Lick system, are measured in the optical and near infra-red (NIR). The 24 indices…

Astrophysics · Physics 2008-11-26 R. N. Proctor , A. E. Sansom

We present new stellar population models of Lick absorption-line indices with variable element abundance ratios. The models are based on our new calibrations of absorption-line indices with stellar parameters derived from the MILES stellar…

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

We have extended our evolutionary synthesis code, GALEV, to include Lick/IDS absorption-line indices for both simple and composite stellar population models (star clusters and galaxies), using the polynomial fitting functions of Worthey et…

Astrophysics · Physics 2009-11-11 Thomas Lilly , Uta Fritze-v. Alvensleben

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

Using evolutionary population synthesis, we present integrated spectral energy distributions and absorption-line indices defined by the Lick Observatory image dissector scanner (referred to as Lick/IDS) system, for an extensive set of…

Astrophysics · Physics 2007-05-23 Fenghui Zhang , Zhanwen Han , Lifang Li , Jarrod R. Hurley

In this paper we study the underlying stellar population of a sample of 65 nearby early-type galaxies predominantly located in low density environments. Ages, metallicities and [alpha/Fe] ratios have been derived through the comparison of…

Astrophysics · Physics 2010-10-28 F. Annibali , A. Bressan , R. Rampazzo , W. W. Zeilinger , L. Danese
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