arXiv 2006.091852020-06-16astro-ph.CO

具有亚毫米星系放大偏差的宇宙学：概念的证明

Cosmology with the submillimetre galaxies magnification bias: Proof of concept

L. Bonavera, J. González-Nuevo, M. M. Cueli, T. Ronconi, M. Migliaccio, L. Dunne, A. Lapi, S. J. Maddox, M. Negrello

备注：: accepted in Astronomy & Astrophysics
发表信息：: A&A 639, A128 (2020)
DOI：: 10.1051/0004-6361/202038050

摘要：

上下文正如最近证明的那样，高z亚毫米星系（SMG）是通过引力透镜追踪星系和星系团（重子和暗物质）质量密度分布及其时间演化的理想背景样本。它们的放大偏差，一个弱的引力透镜效应，是一个强有力的工具，约束的自由参数的晕占据分布（HOD）模型，也可能是一些主要的宇宙学参数。目标。本工作的目的是测试作为宇宙学探针的高z SMG上产生的放大率偏差的能力。我们利用互相关数据来约束不仅天体物理参数（$M_{min}$，$M_1$，和$α$），但也有一些宇宙学的（$Ω_m$，$σ_8$，和$H_0$）的概念证明。方法.用传统的晕模型描述了光谱红移在0.2 < z 1.2范围内的GAMA星系的前景样本之间的交叉关联函数< 0.8 and a background sample of H-ATLAS galaxies with photometric redshifts >，该模型依赖于HOD和宇宙学参数。然后，通过使用不同的先验集执行马尔可夫链蒙特卡罗分析来估计这些参数，以测试结果的鲁棒性，并研究这种新的可观察的性能与当前的数据集结果。根据我们目前的结果，$Ω_m$和$H_0$不能很好地约束。然而，我们可以在$Ω_m$上在95%置信水平（CL）下将下限设置为>0.24，并且我们看到$H_0>70$值的轻微趋势。对于我们对$σ_8$的限制，我们仅获得了0.75左右的暂定峰值，但$σ_8\lesssim 1$的有趣上限为95\% CL。我们还研究了通过对天体物理参数施加更多限制性先验来获得更好约束的可能性。

英文摘要：

Context. As recently demonstrated, high-z submillimetre galaxies (SMGs) are the perfect background sample for tracing the mass density profiles of galaxies and clusters (baryonic and dark matter) and their time-evolution through gravitational lensing. Their magnification bias, a weak gravitational lensing effect, is a powerful tool for constraining the free parameters of a halo occupation distribution (HOD) model and potentially also some of the main cosmological parameters. Aims. The aim of this work is to test the capability of the magnification bias produced on high-z SMGs as a cosmological probe. We exploit cross-correlation data to constrain not only astrophysical parameters ($M_{min}$, $M_1$, and $α$), but also some of the cosmological ones ($Ω_m$, $σ_8$, and $H_0$) for this proof of concept. Methods. The measured cross-correlation function between a foreground sample of GAMA galaxies with spectroscopic redshifts in the range 0.2 < z < 0.8 and a background sample of H-ATLAS galaxies with photometric redshifts >1.2 is modelled using the traditional halo model description that depends on HOD and cosmological parameters. These parameters are then estimated by performing a Markov chain Monte Carlo analysis using different sets of priors to test the robustness of the results and to study the performance of this novel observable with the current set of data Results. With our current results, $Ω_m$ and $H_0$ cannot be well constrained. However, we can set a lower limit of >0.24 at 95\% confidence level (CL) on $Ω_m$ and we see a slight trend towards $H_0>70$ values. For our constraints on $σ_8$ we obtain only a tentative peak around 0.75, but an interesting upper limit of $σ_8\lesssim 1$ at 95\% CL. We also study the possibility to derive better constraints by imposing more restrictive priors on the astrophysical parameters.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

摘要：

英文摘要：

相关论文