In this work, I construct a LRG sample with the redshift of 0.6 ≤ z ≤ 0.75 from the Sloan Digital Sky Survey Data Release 15 (SDSS DR15), which contains 184172 CMASS LRGs and 27158 eBOSS LRGs and examine the environmental dependence of the u–r, u–g, g–r, r–i, and i–z colors in this galaxy sample. I divide this LRG sample into subsamples with a redshift binning size of Δz = 0.01, and analyze the environmental dependence of the u–r, u–g, g–r, r–i, and i–z colors for these subsamples in each redshift bin. Overall, the u–r, u–g, g–r, and r–i colors of galaxies in LRG sample with the redshift of 0.6 ≤ z ≤ 0.75 are very weakly correlated with the local environment, which shows that minimal environmental dependence of galaxy parameters can continue to higher redshifts. It is noteworthy that i–z color of this CMASS + eBOSS LRG sample shows substantial correlation with the local environment in the redshift region 0.70 ≤ z ≤ 0.75.

中文翻译：

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0.60 <z <0.75的红移区域中星系的色密度关系

在这项工作中，我们构建了一条LRG样品0.6≤的红移ž ≤0.75斯隆数字巡天数据发布15（SDSS DR15），其中包含184172个CMASS LRGS和27158个eBOSS LRGS并检查U盘的环境依赖性该星系样本中的r，u-g，g-r，r-i和i-z颜色。我把这种LRG样品与Δ的红移合并大小的子样品Ž = 0.01，并分析该U R，U-G，G-R的环境依赖性，R-I和I-Z的颜色对这些子样品在每个Redshift Bin。总体上，该U R，U-G，G-R，和LRG样品中的0.6红移星系的R-I颜色≤ ž≤0.75与当地环境的相关性非常弱，这表明银河参数对环境的最小依赖性可以继续导致更高的红移。值得注意的是，此CMASS + eBOSS LRG样品示出了具有红移区域0.70≤本地环境实质相关的I-z色彩Ž ≤0.75。