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arXiv 2112.04484astro-ph.CO
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从SDSS-III BOSS巡天中对星系内禀排列的场级推断

Field-level inference of galaxy intrinsic alignment from the SDSS-III BOSS survey

Eleni Tsaprazi, Nhat-Minh Nguyen, Jens Jasche, Fabian Schmidt, Guilhem Lavaux

摘要:

当大规模的超密度坍缩时,它会通过沿星系轴施加潮汐切变来影响星系的形成方向和形状。因此,椭圆星系的形状与宇宙结构的潮汐场一致。这种内在的排列提供了对星系形成和原始宇宙的深入了解,补充了晚期宇宙学探测,并构成了弱引力透镜观测的重要系统效应。在本研究中,我们提供的线性对齐模型使用完全贝叶斯场级的方法,使用SDSS-III BOSS LOWZ样本和三维潮汐场的LOWZ和CMASS星系样本的SDSS-III BOSS调查约束的星系形状测量的约束。我们发现4个$σ$的内在对齐的证据,$A_I=2.9 \pm 0.7$的振幅为20 $h^{-1}\;\mathrm{Mpc}$。

英文摘要:

As a large-scale overdensity collapses, it affects the orientation and shape of galaxies that form, by exerting tidal shear along their axes. Therefore, the shapes of elliptical galaxies align with the tidal field of cosmic structures. This intrinsic alignment provides insights into galaxy formation and the primordial universe, complements late-time cosmological probes and constitutes a significant systematic effect for weak gravitational lensing observations. In the present study, we provide constraints on the linear alignment model using a fully Bayesian field-level approach, using galaxy shape measurements from the SDSS-III BOSS LOWZ sample and three-dimensional tidal fields constrained with the LOWZ and CMASS galaxy samples of the SDSS-III BOSS survey. We find 4$σ$ evidence of intrinsic alignment, with an amplitude of $A_I=2.9 \pm 0.7$ at 20$h^{-1}\;\mathrm{Mpc}$.

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