The Impact of Environment on Late-time Evolution of the Stellar Mass–Halo Mass Relation
The Impact of Environment on Late-time Evolution of the Stellar Mass–Halo Mass Relation
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DOI：
10.3847/1538-4357/ab1d55
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发表时间：
2019-01
期刊：
影响因子：
--
通讯作者：
J. Golden-Marx;C. Miller
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文献类型：
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作者：
J. Golden-Marx;C. Miller
在固定的光晕质量下，最亮的中央星系（BCG）和第四亮的星团成员（mgap）之间的亮度差异较大的星团具有较大的BCG恒星质量。最近的研究表明，在星团恒星质量-光晕质量（SMHM）关系中加入mgap作为潜在参数，可以更精确地测量SMHM关系的振幅、斜率和本征散射。我们使用斯隆数字巡天的星系团来测量SMHM-mgap关系及其在z = 0.3范围内的演化。我们使用100 kpc的固定移动孔径来定义中心星系的恒星质量，我们报告了SMHM相对于z = 0.3 （>3.5σ）的斜率在统计上显著的负演化。在过去的3.5 Gyr中，斜率的变陡可以用星系团核心的后期合并活动来解释。我们还发现，推断的斜率取决于用于定义中央星系径向范围的孔径。在小半径处（20kpc）， SMHM关系的斜率较浅，这表明中央星系的核心与下面宿主晕的增长关系较小。通过将所有中央星系的光包括在100kpc内，斜率达到渐近线值。
At a fixed halo mass, galaxy clusters with larger differences in brightness between the brightest central galaxy (BCG) and fourth-brightest cluster member (mgap) have larger BCG stellar masses. Recent studies have shown that by including mgap as a latent parameter in the cluster stellar mass–halo mass (SMHM) relation, one can make more precise measurements of the SMHM relation’s amplitude, slope, and intrinsic scatter. We use galaxy clusters from the Sloan Digital Sky Survey to measure the SMHM–mgap relation and its evolution out to z = 0.3. Using a fixed comoving aperture of 100 kpc to define the central galaxy’s stellar mass, we report statistically significant negative evolution in the slope of the SMHM relation to z = 0.3 (>3.5σ). The steepening of the slope over the past 3.5 Gyr can be explained by late-time merger activity at the cores of galaxy clusters. We also find that the inferred slope depends on the aperture used to define the radial extent of the central galaxy. At small radii (20 kpc), the slope of the SMHM relation is shallow, indicating that the core of the central galaxy is less related to the growth of the underlying host halo. By including all of the central galaxy’s light within 100 kpc, the slope reaches an asymptote value.