The 6dF Galaxy Survey: the near-infrared Fundamental Plane of early-type galaxies
The 6dF Galaxy Survey: the near-infrared Fundamental Plane of early-type galaxies
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6dF 星系巡天：早期型星系的近红外基本平面
DOI：
10.1111/j.1365-2966.2012.21421.x
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发表时间：
2012
影响因子：
4.8
通讯作者：
Caltech
中科院分区：
文献类型：
--
作者：
C. Magoulas;C. Springob;M. Colless;D. Jones;L. Campbell;J. Lucey;J. Mould;T. Jarrett;A. Merson;S. B. U. O. Melbourne;Australian Astronomical Observatory;Monash University;U. Kentucky;U. Durham;Swinburne University;Caltech
我们确定了6度场星系巡天（6dFGS）中~ 10^4早期型星系的近红外基本平面（FP）。采用最大似然方法拟合了中心速度色散、近红外表面亮度和半光半径的三维高斯模型。该模型对观测到的FP分布提供了很好的经验拟合，证明了该方法的鲁棒性和无偏性。使用模拟的测试表明，在所有三个参数中存在显著且相关的不确定性时，通过各种选择效应和数据样本中的异常值对数据进行审查，它提供了优于回归技术的结果。对于6dFGS j波段样品，我们发现R_e∝σ^(1.52±0.03)_0 I_e^（- 0.89±0.01）的FP与以前的近红外测定相似，并且在考虑平均颜色差异的情况下与H和k波段FP一致。在R_e中，关于FP的总体散点是σ_r = 29%，是由观测误差引起的18%的散点和23%的本征散点的正交和。由于星系在FP空间中的高斯分布，σ_r不是距离误差，我们发现σ_d = 23%。使用群体丰富度和局部密度作为环境的度量，以及基于视觉分类的形态，我们发现FP斜率不随环境或形态而变化。然而，对于固定速度色散和表面亮度而言，场星系平均比群星系或高密度环境中的星系大5%，而早期型螺旋星系的凸起平均比椭圆星系和透镜星系大10%。FP残差与环境、形态和恒星种群有显著的变化趋势。最强的趋势是年龄，我们推测年龄是FP抵消的最重要的系统来源，并可能通过其与环境，形态和金属丰度的相关性驱动其他趋势。这些结果将为我们使用近红外FP来推导6dFGS星系的相对距离和特殊速度提供信息。
We determine the near-infrared Fundamental Plane (FP) for ∼10^4 early-type galaxies in the 6-degree Field Galaxy Survey (6dFGS). We fit the distribution of central velocity dispersion, near-infrared surface brightness and half-light radius with a 3D Gaussian model using a maximum-likelihood method. The model provides an excellent empirical fit to the observed FP distribution and the method proves robust and unbiased. Tests using simulations show that it gives superior results to regression techniques in the presence of significant and correlated uncertainties in all three parameters, censoring of the data by various selection effects and outliers in the data sample. For the 6dFGS J-band sample we find an FP with R_e ∝ σ^(1.52±0.03)_0 I_e^(−0.89±0.01), similar to previous near-infrared determinations and consistent with the H- and K-band FPs once allowance is made for differences in mean colour. The overall scatter in R_e about the FP is σ_r = 29 per cent, and is the quadrature sum of an 18 per cent scatter due to observational errors and a 23 per cent intrinsic scatter. Because of the Gaussian distribution of galaxies in FP space, σ_r is not the distance error, which we find to be σ_d = 23 per cent. Using group richness and local density as measures of environment, and morphologies based on visual classifications, we find that the FP slopes do not vary with environment or morphology. However, for fixed velocity dispersion and surface brightness, field galaxies are on average 5 per cent larger than galaxies in groups or higher density environments, and the bulges of early-type spirals are on average 10 per cent larger than ellipticals and lenticulars. The residuals about the FP show significant trends with environment, morphology and stellar population. The strongest trend is with age, and we speculate that age is the most important systematic source of offsets from the FP, and may drive the other trends through its correlations with environment, morphology and metallicity. These results will inform our use of the near-infrared FP in deriving relative distances and peculiar velocities for 6dFGS galaxies.