SPIDER - III。早型半导体基面的环境依赖性
SPIDER - III. Environmental Dependence of the Fundamental Plane of Early-type Galaxies
摘要：
我们分析了$39,993$早型星系（ETG）在光学（griz）波段和$5,080$在近红外（YJHK）波段的基本面（FP）关系，形成了一个$4,589$星系的光学$+$ NIR样本。我们专注于分析的FP作为星系所在的环境的函数。我们使用最大的组目录，三维数据的基础上，从SDSS在低红移（$z < 0.1$）产生的环境。我们发现FP的截距$``c''$从高密度区域到低密度区域平滑地减小，这意味着低密度的星系平均具有比高密度星系更低的质光比。$``c''$也随着母星系群的平均特征质量而减小。然而，这种趋势是弱的，完全占$``c''$与局部密度的变化。FP偏移量的变化在所有波段都是相同的，这意味着低密度的ETG比星系团星系具有更年轻的光度加权年龄，这与星系形成的半分析模型的预期一致。我们测量了局部星系密度每十年的$\sim 0.048$ ~dex（$\sim 11\%$）的年龄变化。这意味着在最高密度区域和磁场区域的星系之间存在大约$32 \%$（$\sim 3 \, Gyr$）的年龄差。发现在$\sim 2$ ~ $σ$处，金属丰度从低密度到高密度逐渐降低.我们还发现了$2.5 \, σ$的证据表明，年龄的变化，每十年的本地密度增加，高达两个因素，星系居住在大规模相对于穷人群体。（节略）
英文摘要：
We analyse the Fundamental Plane (FP) relation of $39,993$ early-type galaxies (ETGs) in the optical (griz) and $5,080$ ETGs in the Near-Infrared (YJHK) wavebands, forming an optical$+$NIR sample of $4,589$ galaxies. We focus on the analysis of the FP as a function of the environment where galaxies reside. We characterise the environment using the largest group catalogue, based on 3D data, generated from SDSS at low redshift ($z < 0.1$). We find that the intercept $``c''$ of the FP decreases smoothly from high to low density regions, implying that galaxies at low density have on average lower mass-to-light ratios than their high-density counterparts. The $``c''$ also decreases as a function of the mean characteristic mass of the parent galaxy group. However, this trend is weak and completely accounted for by the variation of $``c''$ with local density. The variation of the FP offset is the same in all wavebands, implying that ETGs at low density have younger luminosity-weighted ages than cluster galaxies, consistent with the expectations of semi-analytical models of galaxy formation. We measure an age variation of $\sim 0.048$~dex ($\sim 11\%$) per decade of local galaxy density. This implies an age difference of about $32 \%$ ($\sim 3 \, Gyr$) between galaxies in the regions of highest density and the field. We find the metallicity decreasing, at $\sim 2$~$σ$, from low to high density. We also find $2.5 \, σ$ evidence that the variation in age per decade of local density augments, up to a factor of two, for galaxies residing in massive relative to poor groups. (abridged)
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