TY - JOUR
T1 - The 6dF Galaxy Survey
T2 - Stellar population trends across and through the Fundamental Plane
AU - Springob, Christopher M.
AU - Magoulas, Christina
AU - Proctor, Rob
AU - Colless, Matthew
AU - Jones, D. Heath
AU - Kobayashi, Chiaki
AU - Campbell, Lachlan
AU - Lucey, John
AU - Mould, Jeremy
PY - 2012/3
Y1 - 2012/3
N2 - 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, v 1, v 2 and v 3, 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 (v 1 direction) and across the plane (v 3 direction), but show no variation at all along the plane (v 2 direction). The v 2 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 v 2.
AB - 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, v 1, v 2 and v 3, 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 (v 1 direction) and across the plane (v 3 direction), but show no variation at all along the plane (v 2 direction). The v 2 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 v 2.
KW - Galaxies: elliptical and lenticular, cD
KW - Galaxies: evolution
KW - Galaxies: fundamental parameters
KW - Galaxies: structure
UR - http://www.scopus.com/inward/record.url?scp=84863393315&partnerID=8YFLogxK
U2 - 10.1111/j.1365-2966.2011.19900.x
DO - 10.1111/j.1365-2966.2011.19900.x
M3 - Article
SN - 0035-8711
VL - 420
SP - 2773
EP - 2784
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 4
ER -