论文标题
在老板星系的“镜头很低”上
On the "Lensing is Low" of BOSS Galaxies
论文作者
论文摘要
最近，Leauthaud等人发现，Baryon振荡光谱调查（BOSS）星系的小尺度镜头信号比重现观察到的星系星系星体质量功能（SMF）和聚类的Galaxy-Halo连接的标准模型的预测低40％。我们通过对Planck宇宙学上Boss Lowz和CMASS样本的SMF，聚类和镜头进行全面的光晕占用分布（HOD）建模，来重新审视这种“镜头很低”的差异。我们允许卫星星系的选择函数随着恒星质量和光晕质量而变化。对于中心，我们假设他们的选择仅取决于恒星质量，这是由直接测量的Redmapper中央星系的检测部分所告知的。最合适的HOD成功地描述了所有三个可观察结果，而没有过度预测小规模的镜头信号。这表明该模型将boss星系置于正确的光环质量的暗物质光环中，从而消除了镜头最高的信号到最高的一个halo状态中的差异。尽管存在较大的不确定性，但观察到的镜头幅度高于1 mpc/h，与该预测保持不一致，但是，通过在普朗克宇宙学处的聚类来测量的大规模星系偏置牢固地锚定。因此，我们证明，可以通过考虑选择函数的光晕质量依赖性来完全解决低于1 MPC/H的尺度上的“镜头低”差异。在大尺度上需要具有提高精度的镜头测量值，以区分普兰克的偏差和非线性效应与星系 - 霍洛连接的偏差。
Recently, Leauthaud et al discovered that the small-scale lensing signal of Baryon Oscillation Spectroscopic Survey (BOSS) galaxies is up to 40% lower than predicted by the standard models of the galaxy-halo connections that reproduced the observed galaxy stellar mass function (SMF) and clustering. We revisit such "lensing is low" discrepancy by performing a comprehensive Halo Occupation Distribution (HOD) modelling of the SMF, clustering, and lensing of BOSS LOWZ and CMASS samples at Planck cosmology. We allow the selection function of satellite galaxies to vary as a function of stellar mass as well as halo mass. For centrals we assume their selection to depend only on stellar mass, as informed by the directly measured detection fraction of the redMaPPer central galaxies. The best-fitting HOD successfully describes all three observables without over-predicting the small-scale lensing signal. This indicates that the model places BOSS galaxies into dark matter halos of the correct halo masses, thereby eliminating the discrepancy in the one-halo regime where the signal-to-noise of lensing is the highest. Despite the large uncertainties, the observed lensing amplitude above 1 Mpc/h remains inconsistent with the prediction, which is however firmly anchored by the large-scale galaxy bias measured by clustering at Planck cosmology. Therefore, we demonstrate that the "lensing is low" discrepancy on scales below 1 Mpc/h can be fully resolved by accounting for the halo mass dependence of the selection function. Lensing measurements with improved accuracy is required on large scales to distinguish between deviations from Planck and non-linear effects from galaxy-halo connections.
