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Related papers: A Robust Method for the Analysis of Integrated Spe…

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Stellar population models of absorption line indices are an important tool for the analysis of stellar population spectra. They are most accurately modelled through empirical calibrations of absorption line indices with the stellar…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Jonas Johansson , Daniel Thomas , Claudia Maraston

We use Hubble Space Telescope (HST) imaging from the ACS Treasury Survey to determine fits for single population isochrones of 69 Galactic globular clusters. Using robust Bayesian analysis techniques, we simultaneously determine ages,…

Solar and Stellar Astrophysics · Physics 2017-03-03 R. Wagner-Kaiser , A. Sarajedini , T. von Hippel , D. C. Stenning , D. A. van Dyk , E. Jeffery , E. Robinson , N. Stein , J. Anderson , W. H. Jefferys

Spectral indices are useful tools for quantifying the strengths of features in moderate-resolution spectra and relating them to intrinsic stellar parameters. This paper focuses on the 4300AA CH G-band, a classic example of a feature…

Astrophysics · Physics 2009-11-13 Sarah L. Martell , Graeme H. Smith , Michael M. Briley

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 absorption line indices measured in the integrated spectra of globular clusters both from the Galaxy and from M 31. Our samples include 41 Galactic globular clusters, and more than 300 clusters in M 31. The conversion of…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Ricardo P. Schiavon , Nelson Caldwell , Heather Morrison , Paul Harding , Stephane Courteau , Lauren A. MacArthur , Genevieve J. Graves

We investigate the precision of the ages and metallicities of 21,000 mock simple stellar populations (SSPs) determined through full-spectrum fitting. The mock SSPs cover an age range of 6.8 $<$ log (age/yr) $<$ 10.2, for three wavelength…

Astrophysics of Galaxies · Physics 2020-09-09 Randa Asa'd , Paul Goudfrooij

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

We present new measurements of the centers for 65 Milky Way globular clusters. Centers were determined by fitting ellipses to the density distribution within the inner $2\arcmin$ of the cluster center, and averaging the centers of these…

Astrophysics of Galaxies · Physics 2015-05-19 Ryan Goldsbury , Harvey B. Richer , Jay Anderson , Aaron Dotter , Ata Sarajedini , Kristin Woodley

The Lick Fe5015, Fe5270, Fe5335, Mgb and Mg2 indices are presented for 139 candidate SMR stars of different luminosity class studied in Malagnini et al. (2000). Evidence is found for a standard (i.e. [Mg/Fe]~0) Mg vs. Fe relative abundance.…

Astrophysics · Physics 2009-11-07 A. Buzzoni , M. Chavez , M. L. Malagnini , C. Morossi

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

Globular cluster ages provide both an important test of models of globular cluster formation and a powerful method to constrain the assembly history of galaxies. Unfortunately, measuring the ages of unresolved old stellar populations has…

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…

Astrophysics of Galaxies · Physics 2014-11-20 Kristin A. Woodley , William E. Harris , Thomas H. Puzia , Matias Gomez , Gretchen L. H. Harris , Doug Geisler

[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

In this work, we perform a full-spectrum fitting of 350 massive and passive galaxies selected as cosmic chronometers from the LEGA-C ESO public survey to derive their stellar ages, metallicities, and star-formation histories. We extensively…

Cosmology and Nongalactic Astrophysics · Physics 2023-04-10 Kang Jiao , Nicola Borghi , Michele Moresco , Tong-Jie Zhang

In previous papers of the series we used a combination of optical and near-infrared colours to derive constraints on the relative age structure in globular cluster systems. Here, we present the details, strength and limitations of our…

Astrophysics · Physics 2009-11-10 Maren Hempel , Markus Kissler-Patig

Our unified chemical and spectrophotometric evolution code allows to simultaneously study the ISM abundances of a series of elements and the spectral properties of the stellar population in our model galaxies. We use stellar evolutionary…

Astrophysics · Physics 2007-05-23 Uta Fritze - v. Alvensleben

The outer region (0.75--1.25 r_e in the B-band) of the merger-remnant elliptical NGC 3610 is studied using extremely high signal to noise Keck spectra, with a supplementary spectrum of the galaxy center. Stellar population parameters --…

Astrophysics · Physics 2009-11-10 Justin Howell , Jean Brodie , Jay Strader , Duncan Forbes , Robert Proctor

We present a cautionary study exploring the reliability of the H-delta line in the integrated spectra of galaxies for determining galaxy ages. Our database consists of the observed integrated spectra of ~120 early-type galaxies, of 7…

We study the simple-stellar-population-equivalent (SSP-equivalent) age and chemical composition measured from the Lick/IDS line-strength indices of composite stellar populations (CSP). We build two sets of ~30000 CSP models using stellar…

Astrophysics · Physics 2009-11-11 Paolo Serra , Scott C. Trager

Context: The combination of optical and near-infrared (NIR) colours has the potential to break the age/metallicity degeneracy and offers a better metallicity sensitivity than optical colours alone. Previous studies of extragalactic globular…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 A. L. Chies-Santos , S. S. Larsen , E. M. Wehner , H. Kuntschner , J. Strader , J. P. Brodie