GALAXY ENVIRONMENTS OVER COSMIC TIME: THE NON-EVOLVING RADIAL GALAXY DISTRIBUTIONS AROUND MASSIVE GALAXIES SINCE z = 1.6
GALAXY ENVIRONMENTS OVER COSMIC TIME: THE NON-EVOLVING RADIAL GALAXY DISTRIBUTIONS AROUND MASSIVE GALAXIES SINCE z = 1.6
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DOI：
10.1088/0004-637x/769/1/31
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发表时间：
2013-02
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影响因子：
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通讯作者：
T. Tal;P. V. van Dokkum;M. Franx;J. Leja;D. Wake;K. Whitaker
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作者：
T. Tal;P. V. van Dokkum;M. Franx;J. Leja;D. Wake;K. Whitaker
我们使用来自斯隆数字巡天和 NEWFIRM 中波段巡天的数据，对 z = 0.04 和 z = 1.6 之间的四个红移箱中的大质量星系环境进行了统计研究。我们测量了围绕恒定数量密度选定的大质量星系样本的圆柱体中星系的投影径向分布，并利用污染源的统计减法。我们的分析表明，巨大的主星系通常生活在群晕中，并被 2-3 个质量超过主星系质量十分之一的卫星包围。这些卫星中累积的恒星质量大致等于主星系本身的质量。我们进一步发现，在过去 9.5 Gyr 中，大质量初级星系周围星系的径向数密度剖面在斜率或整体归一化方面都没有显着演化。对这一结果的简单解释可以作为研究群体中缺乏合并的证据，并作为对包含大量初选光环的静态演化模型的支持。或者，新卫星的合并和吸积之间存在紧密的平衡，从而保持晕圈内和周围星系的整体分布。后一种解释得到了与半解析模型的比较的支持，半解析模型显示了在相同红移范围内类似的恒定平均卫星分布。
We present a statistical study of the environments of massive galaxies in four redshift bins between z = 0.04 and z = 1.6, using data from the Sloan Digital Sky Survey and the NEWFIRM Medium Band Survey. We measure the projected radial distribution of galaxies in cylinders around a constant number density selected sample of massive galaxies and utilize a statistical subtraction of contaminating sources. Our analysis shows that massive primary galaxies typically live in group halos and are surrounded by 2–3 satellites with masses more than one-tenth of the primary galaxy mass. The cumulative stellar mass in these satellites roughly equals the mass of the primary galaxy itself. We further find that the radial number density profile of galaxies around massive primaries has not evolved significantly in either slope or overall normalization in the past 9.5 Gyr. A simplistic interpretation of this result can be taken as evidence for a lack of mergers in the studied groups and as support for a static evolution model of halos containing massive primaries. Alternatively, there exists a tight balance between mergers and accretion of new satellites such that the overall distribution of galaxies in and around the halo is preserved. The latter interpretation is supported by a comparison to a semi-analytic model, which shows a similar constant average satellite distribution over the same redshift range.