arXiv 1208.20972012-08astro-ph.CO

高红移Lyman Break Galerkin的空间团簇

Spatial Clustering of High Redshift Lyman Break Galaxies

Charles Jose, Kandaswamy Subramanian, Raghunathan Srianand, Saumyadip Samui

备注：: Accepted for publication in MNRAS
DOI：: 10.1093/mnras/sts503

摘要：

我们提出了一个物理驱动的半解析模型来理解高红移LBG的集群。结果表明，在观测光度函数的约束下，模型参数可用于预测大尺度（θ> 80角秒）星系的偏差和角关联函数。这些预测显示出非常好地再现了观测结果。然后，我们采用这些模型参数计算晕占据分布（HOD）使用的条件质量函数。使用这种HOD的晕模型显示出在z=3-5和几个极限星等的大（θ>80”）和小（θ< 10”）角尺度下对所观察到的LBG聚类提供了相当好的拟合。然而，我们的模型低估了集群幅度在中间的角度尺度，准线性效应是重要的。在z=4的极限绝对星等为-20.5时，对观测到的星系团有贡献的晕的平均质量为6.2 x 10^{11} M_ \odot，而母晕中卫星星系的特征质量为1.2 \times 10^{12} M_ \odot。对于一个给定的阈值亮度，这些质量随着z的增加而减少，在任何给定的z，这些被发现增加阈值亮度的值。我们发现，大约40%的晕在最小质量M_{min}以上，可以容纳可探测的中央星系，大约5- 10%的晕也可能容纳可探测的卫星。这些卫星通常在母晕形成之前形成一个动态时间尺度。小角度尺度的集群是由于中央卫星对，是相当敏感的变化，恒星形成的时间在晕。目前的数据有利于恒星形成的晕持续几个动态的时间尺度。我们的模型还再现了与恒星形成相关的参数之间的不同已知趋势。

英文摘要：

We present a physically motivated semi-analytic model to understand the clustering of high redshift LBGs. We show that the model parameters constrained by the observed luminosity function, can be used to predict large scale (θ> 80 arcsec) bias and angular correlation function of galaxies. These predictions are shown to reproduce the observations remarkably well. We then adopt these model parameters to calculate the halo occupation distribution (HOD) using the conditional mass function. The halo model using this HOD is shown to provide a reasonably good fit to the observed clustering of LBGs at both large (θ>80") and small (θ< 10") angular scales for z=3-5 and several limiting magnitudes. However, our models underpredict the clustering amplitude at intermediate angular scales, where quasi-linear effects are important. The average mass of halos contributing to the observed clustering is found to be 6.2 x 10^{11} M_\odot and the characteristic mass of a parent halo hosting satellite galaxies is 1.2 \times 10^{12} M_\odot for a limiting absolute magnitude of -20.5 at z=4. For a given threshold luminosity these masses decrease with increasing z and at any given z these are found to increase with increasing value of threshold luminosity. We find that approximately 40 % of the halos above a minimum mass M_{min}, can host detectable central galaxies and about 5-10 % of these halos are likely to also host a detectable satellite. The satellites form typically a dynamical timescale prior to the formation of the parent halo. The small angular scale clustering is due to central-satellite pairs and is quite sensitive to changes in the duration of star formation in a halo. The present data favor star formation in a halo lasting typically for a few dynamical time-scales. Our models also reproduce different known trends between parameters related to star formation.

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