论文标题
用流体动力模拟来限制内在比对模型的进步
Advances in Constraining Intrinsic Alignment Models with Hydrodynamic Simulations
论文作者
论文摘要
我们使用Illustristng,MassiveBlack-II和Illustris流体动力模拟的星系来研究大型星系内在比对的行为。我们的分析跨越了四个红移切片,在当代镜头调查的大致范围内$ z = 0-1 $。我们从三个模拟中构造了可比较的加权样品,然后我们使用包括线性和二次比对贡献的比对模型进行分析。我们的数据矢量包括星系 - 半趋势,星形形状和形状形状的相关性,与联合协方差矩阵进行了分析估计。在所有模拟中,我们在几个$σ$的级别上报告了非零IAS。对于固定的较低质量阈值,我们在所有三个模拟中都发现了相对较强的红移依赖性,线性IA振幅在RedShifts $ z = 0 $和$ z = 1 $之间增加了$ \ sim 2 $。我们报告没有明显的证据表明潮汐扭矩振幅的非零值,$ a_2 $,tng高于统计不确定性,尽管大规模的II偏爱中等的负$ A_2 \ sim-2 $。研究纹身模型的特性是颜色,光度和星系类型(卫星或中央)的函数,我们的发现与实际数据的最新测量结果一致。我们还概述了一种新的方法,该方法直接从像素化的潮汐场直接限制了纹身模型参数,以及使用TNG的概念练习。尽管该技术与以前通过其他方法获得的结果的比较是非平凡的,但该技术表现出很有希望。
We use galaxies from the IllustrisTNG, MassiveBlack-II and Illustris hydrodynamic simulations to investigate the behaviour of large scale galaxy intrinsic alignments. Our analysis spans four redshift slices over the approximate range of contemporary lensing surveys $z=0-1$. We construct comparable weighted samples from the three simulations, which we then analyse using an alignment model that includes both linear and quadratic alignment contributions. Our data vector includes galaxy-galaxy, galaxy-shape and shape-shape projected correlations, with the joint covariance matrix estimated analytically. In all of the simulations, we report non-zero IAs at the level of several $σ$. For a fixed lower mass threshold, we find a relatively strong redshift dependence in all three simulations, with the linear IA amplitude increasing by a factor of $\sim 2$ between redshifts $z=0$ and $z=1$. We report no significant evidence for non-zero values of the tidal torquing amplitude, $A_2$, in TNG, above statistical uncertainties, although MassiveBlack-II favours a moderately negative $A_2\sim-2$. Examining the properties of the TATT model as a function of colour, luminosity and galaxy type (satellite or central), our findings are consistent with the most recent measurements on real data. We also outline a novel method for constraining the TATT model parameters directly from the pixelised tidal field, alongside a proof of concept exercise using TNG. This technique is shown to be promising, although the comparison with previous results obtained via other methods is non-trivial.