Open AccessA catalogue and analysis of local galaxy ages and metallicities
Author(s) -
Terlevich A.I.,
Forbes Duncan A.
Publication year - 2002
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.2002.05073.x
Subject(s) - physics , astrophysics , elliptical galaxy , lenticular galaxy , brightest cluster galaxy , astronomy , galaxy cluster , metallicity , surface brightness fluctuation , galaxy group , galaxy formation and evolution , peculiar galaxy , galaxy , luminous infrared galaxy
We have assembled a catalogue of relative ages, metallicities and abundance ratios for about 150 local galaxies in field, group and cluster environments. The galaxies span morphological types from cD and ellipticals, to late‐type spirals. Ages and metallicities were estimated from high‐quality published spectral line indices using Worthey & Ottaviani (1997) single stellar population evolutionary models. The identification of galaxy age as a fourth parameter in the fundamental plane (Forbes, Ponman & Brown 1998) is confirmed by our larger sample of ages. We investigate trends between age and metallicity, and with other physical parameters of the galaxies, such as ellipticity, luminosity and kinematic anisotropy. We demonstrate the existence of a galaxy age–metallicity relation similar to that seen for local galactic disc stars, whereby young galaxies have high metallicity, while old galaxies span a large range in metallicities. We also investigate the influence of environment and morphology on the galaxy age and metallicity, especially the predictions made by semi‐analytic hierarchical clustering models (HCM). We confirm that non‐cluster ellipticals are indeed younger on average than cluster ellipticals as predicted by the HCM models. However we also find a trend for the more luminous galaxies to have a higher [Mg/Fe] ratio than the lower luminosity galaxies, which is opposite to the expectation from HCM models.