Euclid：第四阶段宇宙剪切实验中的约化剪切近似与放大偏置
宇宙学与河外天体物理
2020-04-29 v3
摘要
第四阶段弱引力透镜实验将在精度上实现超过一个量级的飞跃。因此我们必须确保分析在新时期保持准确。相应地，先前被忽略的系统效应必须得到处理。本工作中，我们评估了约化剪切近似与放大偏置对从角功率谱获取信息的影响。在一阶近似下，约化剪切（剪切与收敛的组合）的统计被取为与剪切的统计相等。然而，这一近似会引入宇宙学参数的偏置，已不能再被忽略。另一独立偏置源于高放大区域中星系的优先选择及其面密度的稀释改变了剪切的统计。这些系统效应的修正形式相似，故可一并处理。我们利用 Fisher 矩阵形式体系并计算了超样本协方差的影响，算出了忽略这些效应对 Euclid 通过宇宙剪切层析所确定的宇宙学参数的影响。我们还展示了如何利用对数正态场前向建模方法计算约化剪切修正。这些效应在 Omega_m、sigma_8、n_s、Omega_DE、w_0 和 w_a 上分别引起 -0.53 sigma、0.43 sigma、-0.34 sigma、1.36 sigma、-0.68 sigma 和 1.21 sigma 的显著偏置。我们随后表明这些透镜偏置与另一系统效应——星系内禀对齐——相互作用。据此，我们发展了内禀对齐增强的透镜偏置修正形式体系。将其应用于 Euclid，我们发现该修正引入的附加项处于次要地位。
引用
@article{arxiv.1912.07326,
title = {Euclid: The reduced shear approximation and magnification bias for Stage IV cosmic shear experiments},
author = {A. C. Deshpande and T. D. Kitching and V. F. Cardone and P. L. Taylor and S. Casas and S. Camera and C. Carbone and M. Kilbinger and V. Pettorino and Z. Sakr and D. Sapone and I. Tutusaus and N. Auricchio and C. Bodendorf and D. Bonino and M. Brescia and V. Capobianco and J. Carretero and M. Castellano and S. Cavuoti and R. Cledassou and G. Congedo and L. Conversi and L. Corcione and M. Cropper and F. Dubath and S. Dusini and G. Fabbian and E. Franceschi and M. Fumana and B. Garilli and F. Grupp and H. Hoekstra and F. Hormuth and H. Israel and K. Jahnke and S. Kermiche and B. Kubik and M. Kunz and F. Lacasa and S. Ligori and P. B. Lilje and I. Lloro and E. Maiorano and O. Marggraf and R. Massey and S. Mei and M. Meneghetti and G. Meylan and L. Moscardini and C. Padilla and S. Paltani and F. Pasian and S. Pires and G. Polenta and M. Poncet and F. Raison and J. Rhodes and M. Roncarelli and R. Saglia and P. Schneider and A. Secroun and S. Serrano and G. Sirri and J. L. Starck and F. Sureau and A. N. Taylor and I. Tereno and R. Toledo-Moreo and L. Valenziano and Y. Wang and J. Zoubian},
journal= {arXiv preprint arXiv:1912.07326},
year = {2020}
}
备注
16 pages, 6 figures, submitted to Astronomy & Astrophysics on 16/12/2019, accepted on 04/03/2020. SSC Fisher procedure corrected