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arXiv 1608.05084astro-ph.GA
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PRIMUS:在$0.2 < z < 1$上的一个和两个晕星系整合

PRIMUS: One- and Two-Halo Galactic Conformity at $0.2 < z < 1$

Angela M. Berti, Alison L. Coil, Peter S. Behroozi, Daniel J. Eisenstein, Aaron D. Bray, Richard J. Cool, John Moustakas

摘要:

我们测试银河系的一致性在$0.2<z<1.0$的投影距离为5百万秒差距使用光谱红移从棱镜多对象调查(PRIMUS)。我们的样本由五个独立区域的$\sim60,000$星系组成,总共覆盖$\sim5.5$平方度,这使我们能够解释宇宙的变化。我们确定了恒星形成和静止的“孤立的主要”(即,中心)星系使用隔离标准和削减特定的恒星形成率。我们匹配这些样本的红移和恒星质量分布,以控制静态分数和红移和恒星质量之间的相关性。我们检测到一个显着的$(>3σ)$一晕一致性信号,或恒星形成的中心星系周围的恒星形成的邻居,$\sim5$ %的尺度为0-1百万秒差距和$2.5σ$两晕信号的$\sim1$ %的尺度为1-3百万秒差距。这些信号比SDSS中检测到的信号弱,并且与大规模潮汐场和反映装配偏差的结果的银河系一致。我们还测量了在固定恒星质量的中央星系的恒星形成分数作为大尺度环境的函数,发现中央星系更容易在过密环境中淬灭,与恒星质量无关。然而,我们发现环境并不影响中心星系的恒星形成效率,只要它们正在形成恒星。我们测试的红移和恒星质量的一致性信号在我们的样本的依赖性,并表明,大的体积和多个领域需要在中间的红移,以充分考虑宇宙方差。

英文摘要:

We test for galactic conformity at $0.2<z<1.0$ to a projected distance of 5 Mpc using spectroscopic redshifts from the PRism MUlti-object Survey (PRIMUS). Our sample consists of $\sim60,000$ galaxies in five separate fields covering a total of $\sim5.5$ square degrees, which allows us to account for cosmic variance. We identify star-forming and quiescent "isolated primary" (i.e., central) galaxies using isolation criteria and cuts in specific star formation rate. We match the redshift and stellar mass distributions of these samples, to control for correlations between quiescent fraction and redshift and stellar mass. We detect a significant $(>3σ)$ one-halo conformity signal, or an excess of star-forming neighbors around star-forming central galaxies, of $\sim5$% on scales of 0-1 Mpc and a $2.5σ$ two-halo signal of $\sim1$% on scales of 1-3 Mpc. These signals are weaker than those detected in SDSS and are consistent with galactic conformity being the result of large-scale tidal fields and reflecting assembly bias. We also measure the star-forming fraction of central galaxies at fixed stellar mass as a function of large-scale environment and find that central galaxies are more likely to be quenched in overdense environments, independent of stellar mass. However, we find that environment does not affect the star formation efficiency of central galaxies, as long as they are forming stars. We test for redshift and stellar mass dependence of the conformity signal within our sample and show that large volumes and multiple fields are required at intermediate redshift to adequately account for cosmic variance.

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