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首页> 外文期刊>The Astrophysical journal >Southern Sky Redshift Survey: Clustering of Local Galaxies*
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Southern Sky Redshift Survey: Clustering of Local Galaxies*

机译:南方天空红移调查:本地星系的聚类*

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We use the two-point correlation function to calculate the clustering properties of the recently completed SSRS2 survey, which probes two well-separated regions of the sky, allowing one to evaluate the sensitivity of sample-to-sample variations. Taking advantage of the large number of galaxies in the combined sample, we also investigate the dependence of clustering on the internal properties of galaxies. The redshift-space correlation function for the combined magnitude-limited sample of the SSRS2 is given by ξ(s) = [s/(5.85 h-1 Mpc)]-1.60 for separations in the range 2 h-1 Mpc ≤ s ≤ 11 h-1 Mpc, while our best estimate for the real-space correlation function is ξ(r) = [r/(5.36 h-1 Mpc)]-1.86. Both are comparable with previous measurements using surveys of optical galaxies over much larger and independent volumes. By comparing the correlation function calculated in redshift and real space, we find that the redshift distortion on intermediate scales is small. This result implies that the observed redshift-space distribution of galaxies is close to that in real space and that β = Ω0.6/b 1, where Ω is the cosmological density parameter and b is the linear biasing factor for optical galaxies. We have used the SSRS2 sample to study the dependence of ξ on the internal properties of galaxies, such as luminosity, morphology, and color. We confirm earlier results that luminous galaxies (L L*) are more clustered than sub-L* galaxies and that the luminosity segregation is scale-independent. We also find that early types are more clustered than late types. However, in the absence of rich clusters, the relative bias between early and late types in real space, bE+S0/bS ~ 1.2, is not as strong as previously estimated. Furthermore, both morphologies present a luminosity-dependent bias, with the early types showing a slightly stronger dependence on luminosity. We also find that red galaxies are significantly more clustered than blue ones, with a mean relative bias of bR/bB ~ 1.4, stronger than that observed for morphology. Finally, by comparing our results with the measurements obtained from the infrared-selected galaxies, we determine that the relative bias between optical and IRAS galaxies in real space is bo/bI ~ 1.4.
机译:我们使用两点相关函数来计算最近完成的SSRS2调查的聚类属性,该调查探测了天空的两个分隔良好的区域,从而可以评估样本间差异的敏感性。利用合并样本中大量的星系,我们还研究了聚类对星系内部特性的依赖性。对于2 h-1 Mpc≤s≤范围内的分离,SSRS2的组合幅度受限样本的红移空间相关函数由ξ(s)= [s /(5.85 h-1 Mpc)]-1.60给出11 h-1 Mpc,而我们对实空间相关函数的最佳估计是ξ(r)= [r /(5.36 h-1 Mpc)]-1.86。两者都可以与以前使用更大和独立体积的光学星系的测量结果进行比较。通过比较在红移和实空间中计算的相关函数,我们发现中间尺度的红移失真很小。该结果表明,观测到的星系的红移空间分布接近于实际空间中的分布,并且β=Ω0.6/ b <1,其中Ω是宇宙学密度参数,b是光学星系的线性偏置因子。我们已经使用SSRS2样本研究了ξ对星系内部特性(例如光度,形态和颜色)的依赖性。我们确认了较早的结果,即发光星系(L> L *)比次L *星系更聚类,并且光度分离与尺度无关。我们还发现,早期类型比晚期类型更加聚集。但是,在没有丰富簇的情况下,实际空间中早期和晚期类型之间的相对偏差bE + S0 / bS〜1.2,不如先前估计的强。此外,两种形态都表现出光度依赖性,早期类型显示出对光度的依赖性稍强。我们还发现,红色星系的聚类比蓝色星系的聚得多,平均相对偏差为bR / bB〜1.4,比形态观察到的强。最后,通过将我们的结果与从红外选择星系获得的测量结果进行比较,我们确定实际空间中光学和IRAS星系之间的相对偏差为bo / bI〜1.4。

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