Skip to content
Back to outputs

The epochs of early-type galaxy formation as a function of environment

Research output: Contribution to journalArticle

Standard

The epochs of early-type galaxy formation as a function of environment. / Thomas, D; Maraston, C; Bender, Ralf; De Oliveira, Claudia Mendes.

In: The Astrophysical Journal, Vol. 621, No. 2, 10.03.2005, p. 673-694.

Research output: Contribution to journalArticle

Harvard

Thomas, D, Maraston, C, Bender, R & De Oliveira, CM 2005, 'The epochs of early-type galaxy formation as a function of environment', The Astrophysical Journal, vol. 621, no. 2, pp. 673-694.

APA

Thomas, D., Maraston, C., Bender, R., & De Oliveira, C. M. (2005). The epochs of early-type galaxy formation as a function of environment. The Astrophysical Journal, 621(2), 673-694.

Vancouver

Thomas D, Maraston C, Bender R, De Oliveira CM. The epochs of early-type galaxy formation as a function of environment. The Astrophysical Journal. 2005 Mar 10;621(2):673-694.

Author

Thomas, D ; Maraston, C ; Bender, Ralf ; De Oliveira, Claudia Mendes. / The epochs of early-type galaxy formation as a function of environment. In: The Astrophysical Journal. 2005 ; Vol. 621, No. 2. pp. 673-694.

Bibtex

@article{df604654b8a1433088211c82e6a309a3,
title = "The epochs of early-type galaxy formation as a function of environment",
abstract = "The aim of this paper is to set constraints of the epochs of early-type galaxy formation through the 'archaeology' of the stellar populations in local galaxies. Using our models of absorption line indices that account for variable abundance ratios, we derive the stellar population parameters of 124 early-type galaxies in high and low density environments. We find that all three parameters age, metallicity, and alpha/Fe ratio are correlated with velocity dispersion. We further find evidence for an influence of the environment on the stellar population properties. Massive early-type galaxies in low-density environments appear on average ~2 Gyrs younger and slightly more metal-rich than their counterparts in high density environments. No offsets in the alpha/Fe ratios, instead, are detected. We translate the derived ages and alpha/Fe ratios into star formation histories. We show that most star formation activity in early-type galaxies is expected to have happened between redshifts 3 and 5 in high density and between redshifts 1 and 2 in low density environments. We conclude that at least 50 per cent of the total stellar mass density must have already formed at z 1, in good agreement with observational estimates of the total stellar mass density as a function of redshift. Our results suggest that significant mass growth in the early-type galaxy population below z 1 must be restricted to less massive objects, and a significant increase of the stellar mass density between redshifts 1 and 2 should be present caused mainly by the field galaxy population. The results of this paper further imply vigorous star formation episodes in massive objects at z 2-5 and the presence of evolved ellipticals around z 1, both observationally identified as SCUBA galaxies and EROs.",
keywords = "galaxies : abundances, galaxies : elliptical and lenticular, cD, galaxies : evolution, galaxies : formation, galaxies : stellar content",
author = "D Thomas and C Maraston and Ralf Bender and {De Oliveira}, {Claudia Mendes}",
year = "2005",
month = "3",
day = "10",
language = "English",
volume = "621",
pages = "673--694",
journal = "The Astrophysical Journal",
issn = "0004-637X",
publisher = "IOP Publishing",
number = "2",

}

RIS

TY - JOUR

T1 - The epochs of early-type galaxy formation as a function of environment

AU - Thomas, D

AU - Maraston, C

AU - Bender, Ralf

AU - De Oliveira, Claudia Mendes

PY - 2005/3/10

Y1 - 2005/3/10

N2 - The aim of this paper is to set constraints of the epochs of early-type galaxy formation through the 'archaeology' of the stellar populations in local galaxies. Using our models of absorption line indices that account for variable abundance ratios, we derive the stellar population parameters of 124 early-type galaxies in high and low density environments. We find that all three parameters age, metallicity, and alpha/Fe ratio are correlated with velocity dispersion. We further find evidence for an influence of the environment on the stellar population properties. Massive early-type galaxies in low-density environments appear on average ~2 Gyrs younger and slightly more metal-rich than their counterparts in high density environments. No offsets in the alpha/Fe ratios, instead, are detected. We translate the derived ages and alpha/Fe ratios into star formation histories. We show that most star formation activity in early-type galaxies is expected to have happened between redshifts 3 and 5 in high density and between redshifts 1 and 2 in low density environments. We conclude that at least 50 per cent of the total stellar mass density must have already formed at z 1, in good agreement with observational estimates of the total stellar mass density as a function of redshift. Our results suggest that significant mass growth in the early-type galaxy population below z 1 must be restricted to less massive objects, and a significant increase of the stellar mass density between redshifts 1 and 2 should be present caused mainly by the field galaxy population. The results of this paper further imply vigorous star formation episodes in massive objects at z 2-5 and the presence of evolved ellipticals around z 1, both observationally identified as SCUBA galaxies and EROs.

AB - The aim of this paper is to set constraints of the epochs of early-type galaxy formation through the 'archaeology' of the stellar populations in local galaxies. Using our models of absorption line indices that account for variable abundance ratios, we derive the stellar population parameters of 124 early-type galaxies in high and low density environments. We find that all three parameters age, metallicity, and alpha/Fe ratio are correlated with velocity dispersion. We further find evidence for an influence of the environment on the stellar population properties. Massive early-type galaxies in low-density environments appear on average ~2 Gyrs younger and slightly more metal-rich than their counterparts in high density environments. No offsets in the alpha/Fe ratios, instead, are detected. We translate the derived ages and alpha/Fe ratios into star formation histories. We show that most star formation activity in early-type galaxies is expected to have happened between redshifts 3 and 5 in high density and between redshifts 1 and 2 in low density environments. We conclude that at least 50 per cent of the total stellar mass density must have already formed at z 1, in good agreement with observational estimates of the total stellar mass density as a function of redshift. Our results suggest that significant mass growth in the early-type galaxy population below z 1 must be restricted to less massive objects, and a significant increase of the stellar mass density between redshifts 1 and 2 should be present caused mainly by the field galaxy population. The results of this paper further imply vigorous star formation episodes in massive objects at z 2-5 and the presence of evolved ellipticals around z 1, both observationally identified as SCUBA galaxies and EROs.

KW - galaxies : abundances

KW - galaxies : elliptical and lenticular, cD

KW - galaxies : evolution

KW - galaxies : formation

KW - galaxies : stellar content

M3 - Article

VL - 621

SP - 673

EP - 694

JO - The Astrophysical Journal

JF - The Astrophysical Journal

SN - 0004-637X

IS - 2

ER -

ID: 1795428