The 6dF Galaxy Survey: Stellar population trends across and through the Fundamental Plane
Date
2012
Authors
Springob, Christopher M
Magoulas, Christine
Proctor, Rob
Colless, Matthew
Jones, D Heath
Kobayashi, Chiaki
Campbell, Lachlan
Lucey, John
Mould, Jeremy
Journal Title
Journal ISSN
Volume Title
Publisher
Blackwell Publishing Ltd
Abstract
We present results from an analysis of stellar population parameters for 7132 galaxies in the 6dF Galaxy Survey Fundamental Plane (FP) sample. We bin the galaxies along the axes, v1, v2 and v3, of the tri-variate Gaussian to which we have fitted the galaxy distribution in effective radius, surface brightness and central velocity dispersion (FP space), and compute median values of stellar age, [Fe/H], [Z/H] and [α/Fe]. We determine the directions of the vectors in FP space along which each of the binned stellar population parameters vary most strongly. In contrast to previous work, we find stellar population trends not just with velocity dispersion and FP residual, but with radius and surface brightness as well. The most remarkable finding is that the stellar population parameters vary through the plane (v1 direction) and across the plane (v3 direction), but show no variation at all along the plane (v2 direction). The v2 direction in FP space roughly corresponds to 'luminosity density'. We interpret a galaxy's position along this vector as being closely tied to its merger history, such that early-type galaxies with lower luminosity density are more likely to have undergone major mergers. This conclusion is reinforced by an examination of the simulations of Kobayashi, which show clear trends of merger history with v2.
Description
Keywords
Keywords: Galaxies: elliptical and lenticular, cD; Galaxies: evolution; Galaxies: fundamental parameters; Galaxies: structure
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Source
Monthly Notices of the Royal Astronomical Society
Type
Journal article
Book Title
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Access Statement
Open Access