标题： 星系际源屏蔽引起的CMB透镜重建偏差 显示英文标题

标题： CMB lensing reconstruction biases from masking extragalactic sources

摘要： 观测到的宇宙微波背景（CMB）地图受到前景污染的影响，其中一些通常被屏蔽以进行宇宙学分析。如果屏蔽与透镜信号相关，例如那些移除位于物质过密区域的星系外发射的屏蔽，那么未屏蔽天空上的测量可能会导致有偏估计。 我们量化了这些由屏蔽引起的偏差对重建的CMB透镜自相关和外部物质追踪器交叉相关功率谱的影响。我们表明，这些偏差既来源于透镜功率的变化，也通过修改透镜功率谱校正项$N_L^{(0)}$、$N_L^{(1)}$和$N_L^{(3/2)}$引起。 对于直接屏蔽CMB透镜场的情况，我们推导了屏蔽效应的简单解析模型，并表明其可能很大。 我们表明，在透镜重建过程中，通过最优滤波可以显著减少屏蔽引起的偏差。 我们在数值模拟中测试了由此产生的透镜功率谱偏差，屏蔽射电源以及热Sunyaev-Zeldovich（tSZ）和宇宙红外背景（CIB）发射峰。 对于透镜自谱，只有未来数据集才能以统计显著性$\lesssim 3\sigma$测量屏蔽偏差。 同样适用于CMB透镜与tSZ和CIB之间的交叉谱功率，尽管偏差更大（最高可达约30%）。 我们发现，屏蔽tSZ选择的星系团会导致最大的屏蔽偏差，可能以高显著性检测到。 我们发现，使用CMB透镜校准星团质量时，特别是对于$z\lesssim 0.6$处的对象，在近未来的观测中，如果未对屏蔽孔内恢复的透镜信号进行进一步修正，则可能会受到屏蔽偏差的重大影响。 相反，高红移物体的质量校准仍会提供无偏结果。 显示英文摘要

摘要： Observed Cosmic Microwave Background (CMB) maps are contaminated by foregrounds, some of which are usually masked to perform cosmological analyses. If masks are correlated to the lensing signal, such as those removing extragalactic emissions located in matter overdensities, measurements over the unmasked sky may give biased estimates. We quantify the impact of these mask-induced biases for the reconstructed CMB lensing auto- and cross-correlation power spectra with external matter tracers. We show that they arise both from changes in the lensing power, and via modifications to the reconstruction power spectrum corrections, $N_L^{(0)}$, $N_L^{(1)}$ and $N_L^{(3/2)}$). For direct masking of the CMB lensing field, we derive simple analytic models of the masking effect and show that it is potentially large. We show that mask-induced biases are significantly reduced by optimal filtering of the CMB maps in the lensing reconstruction. We test the resulting lensing power spectrum biases on numerical simulations, masking radio sources, and peaks of thermal Sunyaev-Zeldovich (tSZ) and cosmic infrared background (CIB) emission. For the lensing auto spectrum, masking biases can only be measured with a statistical significance $\lesssim 3\sigma$ for future data sets. The same applies to the cross-correlation power spectra between CMB lensing and tSZ and CIB even though biases are larger (up to ~30%). We find that masking tSZ-selected galaxy clusters leads to the largest mask biases, potentially detectable with high significance. We find that the calibration of cluster masses using CMB lensing, in particular for objects at $z\lesssim 0.6$, might be significantly affected by mask biases for near-future observations if the lensing signal recovered inside the mask holes is used without further corrections. Conversely, mass calibration of high redshift objects will still deliver unbiased results.