Stellar populations of early-type galaxies in different environments - III. Line-strength gradients
TLDR
In this paper, the authors studied the stellar content of early-type galaxies and derived the age and metallicity gradients for 22 spectral indices measured in a sample of 82 early type galaxies in different environments, including the high density cores of the Coma cluster, the Virgo cluster, poor groups, and isolated field galaxies.Abstract:
Aims This is the third paper of a series devoted to the study of the stellar content of early-type galaxies The goal of the series is to set constraints on the evolutionary status of these objects Methods We present line-strength gradients for 22 spectral indices measured in a sample of 82 early-type galaxies in different environments, including the high-density cores of the Coma cluster, the Virgo cluster, poor groups, and isolated field galaxies Using new evolutionary population synthesis models, we derive age and metallicity gradients, and compare the mean values with the predictions of different galaxy formation models We explore the behaviour of individual chemical species by deriving the metallicity gradient with different indicators Results We find that the strength of the metallicity gradient inferred from stellar population models depends on the specific Lick index employed In particular, metallicity gradients obtained with CN2 and C4668 combined with H beta are steeper than those measured using Ca4227 or Fe4383 The correlation of the metallicity gradients with other parameters also depends on the specific index employed If the metallicity gradient is obtained using CN2 and Mgb, then it correlates with the central age of the galaxies On the contrary, if Fe4383 or Ca4227 is used, the metallicity gradient correlates with the velocity dispersion gradient Conclusions This may suggest that several mechanisms have helped to set the age and metallicity gradients in early-type galaxies While we do not find any correlation between the metallicity gradient and the central velocity dispersion for galaxies in low-density environments, we find a marginal correlation between the metallicity gradient and the mass for galaxies in the centre of the Coma cluster We also find a trend for which galaxies in denser environments show a steeper metallicity gradient than galaxies in less dense environments We interpret these results in light of the different mechanisms proposed to explain the observed changes between galaxies as a function of environmentread more
Citations
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Evolutionary stellar population synthesis with MILES: I. The base models and a new line index system
Alexandre Vazdekis,Alexandre Vazdekis,Patricia Sanchez-Blazquez,Patricia Sanchez-Blazquez,Jesús Falcón-Barroso,Jesús Falcón-Barroso,A. J. Cenarro,A. J. Cenarro,Michael A. Beasley,Nicolás Cardiel,Javier Gorgas,Reynier Peletier +11 more
TL;DR: In this paper, the authors presented synthetic spectral energy distributions (SEDs) for single-age, single-metallicity stellar populations (SSPs) covering the full optical spectral range at moderately high resolution [full width at half-maximum (FWHM) = 2.3A].
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De re metallica: the cosmic chemical evolution of galaxies
TL;DR: In this paper, the authors provide an overview of the methods used to constrain the chemical enrichment in galaxies and their environment, and discuss the observed scaling relations between metallicity and galaxy properties, the observed relative chemical abundances, how the chemical elements are distributed within galaxies, and how these properties evolve across the cosmic epochs.
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Superdense massive galaxies in the nearby universe
Ignacio Trujillo,A. Javier Cenarro,Adriana de Lorenzo-Cáceres,Alexandre Vazdekis,Ignacio G. de la Rosa,Antonio Cava +5 more
TL;DR: In this paper, the authors used the NYU Value-Added Galaxy Catalog from the Sloan Digital Sky Survey Data Release 6 to find only a tiny fraction of galaxies (~0.03%) with re 1.5 kpc and M 8 × 1010 M ☉ in the local universe.
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Spatially resolved spectroscopy of early-type galaxies over a range in mass
Patricia Sanchez-Blazquez,Patricia Sanchez-Blazquez,Patricia Sanchez-Blazquez,Duncan A. Forbes,Jay Strader,Jean P. Brodie,Robert N. Proctor +6 more
TL;DR: In this article, a sample of 11 early-type galaxies covering a wide range in luminosity and hence mass was used to derive ages, metallicities and α/Fe abundances along the radius.
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Age and metallicity gradients in early-type galaxies: A dwarf to giant sequence
TL;DR: In this article, the stellar populations of 40 early-type galaxies using medium-resolution long-slit spectroscopy along their major axes (and along the minor axis for two of them).
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