论文标题

完整的$ W $ CDM分析儿童1000弱镜头图,使用深度学习

A Full $w$CDM Analysis of KiDS-1000 Weak Lensing Maps using Deep Learning

论文作者

Fluri, Janis, Kacprzak, Tomasz, Lucchi, Aurelien, Schneider, Aurel, Refregier, Alexandre, Hofmann, Thomas

论文摘要

我们使用图形扭转神经网络(GCNN)进行了完整的前向模型$ W $ CDM分析,对儿童1000弱镜头图。利用$ \ texttt {cosmogrid} $,这是一个跨越六个不同宇宙学参数的新型大型仿真套件,我们在球体上产生了将近一百万个断层扫描模拟调查。由于数据集的大小和调查区域,我们执行球形分析,同时将地图分辨率限制为$ \ texttt {healpix} $ $ $ n_ \ mathrm {side} = 512 $。我们在系统学上的边缘化,例如光度红移误差,乘法校准和添加剪切偏置。此外,我们使用非线性内在比对模型的地图级实现,以及对重型反馈的新处理,以结合其他天体物理滋扰参数。我们还执行球形功率谱分析以进行比较。宇宙学参数的约束是使用称为高斯过程近似贝叶斯计算(GPABC)的可能性的无可能推理方法生成的。最后,我们检查我们的管道是否可以在模拟参数的选择中进行健壮。我们发现对$ s_8 \equivσ_8\ sqrt {ω_m/0.3} = 0.78^{+0.06} _ { - 0.06} $的限制,对于我们的功率谱分析,$ s_8 = 0.79 = 0.79^{+0.05}^{+0.05} = 0.05} 16%。这与对2分函数的早期分析是一致的,尽管略高。重型校正通常会将对退化参数的约束扩大约10%。这些结果为基于机器学习的全面分析提供了巨大的前景,对正在进行的和未来的弱镜头调查的分析。

We present a full forward-modeled $w$CDM analysis of the KiDS-1000 weak lensing maps using graph-convolutional neural networks (GCNN). Utilizing the $\texttt{CosmoGrid}$, a novel massive simulation suite spanning six different cosmological parameters, we generate almost one million tomographic mock surveys on the sphere. Due to the large data set size and survey area, we perform a spherical analysis while limiting our map resolution to $\texttt{HEALPix}$ $n_\mathrm{side}=512$. We marginalize over systematics such as photometric redshift errors, multiplicative calibration and additive shear bias. Furthermore, we use a map-level implementation of the non-linear intrinsic alignment model along with a novel treatment of baryonic feedback to incorporate additional astrophysical nuisance parameters. We also perform a spherical power spectrum analysis for comparison. The constraints of the cosmological parameters are generated using a likelihood free inference method called Gaussian Process Approximate Bayesian Computation (GPABC). Finally, we check that our pipeline is robust against choices of the simulation parameters. We find constraints on the degeneracy parameter of $S_8 \equiv σ_8\sqrt{Ω_M/0.3} = 0.78^{+0.06}_{-0.06}$ for our power spectrum analysis and $S_8 = 0.79^{+0.05}_{-0.05}$ for our GCNN analysis, improving the former by 16%. This is consistent with earlier analyses of the 2-point function, albeit slightly higher. Baryonic corrections generally broaden the constraints on the degeneracy parameter by about 10%. These results offer great prospects for full machine learning based analyses of on-going and future weak lensing surveys.

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