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arXiv 1802.00734astro-ph.CO
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通过Halo模型、KiDS和GAMA揭示星系偏差

Unveiling Galaxy Bias via the Halo Model, KiDS and GAMA

Andrej Dvornik, Konrad Kuijken, Henk Hoekstra, Peter Schneider, Alexandra Amon, Reiko Nakajima, Massimo Viola, Ami Choi, Thomas Erben, Daniel J. Farrow, Catheri… 展开作者

Andrej Dvornik, Konrad Kuijken, Henk Hoekstra, Peter Schneider, Alexandra Amon, Reiko Nakajima, Massimo Viola, Ami Choi, Thomas Erben, Daniel J. Farrow, Catherine Heymans, Hendrik Hildebrandt, Cristóbal Sifón, Lingyu Wang

备注：
23 pages, 9 figures, accepted for publication in MNRAS
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摘要：

我们使用星系和质量大会（GAMA）巡天和千度巡天（KiDS）测量投影星系团和星系-星系透镜信号，以研究星系偏差。我们使用的概念，非线性和随机星系偏置的框架内的晕占领统计约束的参数，晕占领统计和揭示星系偏置的起源。偏置函数$Γ_{\text{gm}}(r_{\text{p}})$，其中$r_{\text{p}}$是预计的共动分离，使用分析晕模型，从$Γ_{\text{gm}}(r_{\text{p}})$的尺度依赖性，和起源的非线性和随机性晕占领模型可以推断。我们的观测揭示了非线性和随机性的物理原因，进一步探索使用流体动力学模拟，与随机性主要源于非泊松行为的卫星星系的暗物质晕和它们的空间分布，这并不遵循的空间分布的暗物质的晕。观测到的非线性主要是由于中央星系的存在，正如以前关于同一主题的理论工作所指出的那样。我们还看到，总的来说，更大质量的星系揭示了更强的尺度依赖性，并且具有更大的半径。我们的研究结果表明，丰富的信息，星系的偏见是隐藏在晕占领模型。因此，这些模型应该用来确定宇宙学研究中星系偏差的影响。

英文摘要：

We measure the projected galaxy clustering and galaxy-galaxy lensing signals using the Galaxy And Mass Assembly (GAMA) survey and Kilo-Degree Survey (KiDS) to study galaxy bias. We use the concept of non-linear and stochastic galaxy biasing in the framework of halo occupation statistics to constrain the parameters of the halo occupation statistics and to unveil the origin of galaxy biasing. The bias function $Γ_{\text{gm}}(r_{\text{p}})$, where $r_{\text{p}}$ is the projected comoving separation, is evaluated using the analytical halo model from which the scale dependence of $Γ_{\text{gm}}(r_{\text{p}})$, and the origin of the non-linearity and stochasticity in halo occupation models can be inferred. Our observations unveil the physical reason for the non-linearity and stochasticity, further explored using hydrodynamical simulations, with the stochasticity mostly originating from the non-Poissonian behaviour of satellite galaxies in the dark matter haloes and their spatial distribution, which does not follow the spatial distribution of dark matter in the halo. The observed non-linearity is mostly due to the presence of the central galaxies, as was noted from previous theoretical work on the same topic. We also see that overall, more massive galaxies reveal a stronger scale dependence, and out to a larger radius. Our results show that a wealth of information about galaxy bias is hidden in halo occupation models. These models should therefore be used to determine the influence of galaxy bias in cosmological studies.

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