Bandpass mismatch error for satellite CMB experiments I: estimating the spurious signal
Bandpass mismatch error for satellite CMB experiments I: estimating the spurious signal
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DOI：
10.1088/1475-7516/2017/12/015
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发表时间：
2017-06
影响因子：
6.4
通讯作者：
D. Hoang;G. Patanchon;M. Bucher;T. Matsumura;R. Banerji;H. Ishino;M. Hazumi;J. Delabrouille
中科院分区：
文献类型：
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作者：
D. Hoang;G. Patanchon;M. Bucher;T. Matsumura;R. Banerji;H. Ishino;M. Hazumi;J. Delabrouille
未来的宇宙微波背景（CMB）卫星任务旨在使用B模式偏振测量张量标量比r，灵敏度为σr <$10 −3。实现这一目标不仅需要足够的探测器阵列灵敏度，而且还需要对CMB偏振测量中固有的所有系统误差进行前所未有的控制。由于偏振测量值来自不同时间和不同传感器的观测值之间的差异，因此检测器响应失配会引入从强度到偏振的泄漏，从而导致伪B模式信号。因为预期的原始B模式偏振信号被已知的非偏振强度信号所矮化，所以这种泄漏可能实质上对测量r的最终误差预算有贡献。利用仿真，我们估计的幅度和角谱的寄生B模式信号的带通失配不同的探测器之间产生的。这里假设检测器被校准，例如使用CMB偶极子，使得它们对原始CMB信号的灵敏度已经完美匹配。因此，探测器之间的频率带通形状的不匹配在银河系发射分量的相对校准中引入了差异。我们使用一系列正在考虑用于未来卫星任务的扫描模式来模拟这种效果。我们发现，在大角度尺度（θ < 10）下，再电离凸块对r的虚假贡献是10 × 10−3，假设有大的探测器阵列和20%的天空被遮蔽。我们展示了泄漏的幅度如何取决于每个像素中的角度覆盖的不均匀性，结果从扫描模式。
Future Cosmic Microwave Background (CMB) satellite missions aim to use the B mode polarization to measure the tensor-to-scalar ratio r with a sensitivity σr ≲ 10−3. Achieving this goal will not only require sufficient detector array sensitivity but also unprecedented control of all systematic errors inherent in CMB polarization measurements. Since polarization measurements derive from differences between observations at different times and from different sensors, detector response mismatches introduce leakages from intensity to polarization and thus lead to a spurious B mode signal. Because the expected primordial B mode polarization signal is dwarfed by the known unpolarized intensity signal, such leakages could contribute substantially to the final error budget for measuring r. Using simulations we estimate the magnitude and angular spectrum of the spurious B mode signal resulting from bandpass mismatch between different detectors. It is assumed here that the detectors are calibrated, for example using the CMB dipole, so that their sensitivity to the primordial CMB signal has been perfectly matched. Consequently the mismatch in the frequency bandpass shape between detectors introduces differences in the relative calibration of galactic emission components. We simulate this effect using a range of scanning patterns being considered for future satellite missions. We find that the spurious contribution to r from the reionization bump on large angular scales (ℓ < 10) is ≈ 10−3 assuming large detector arrays and 20 percent of the sky masked. We show how the amplitude of the leakage depends on the nonuniformity of the angular coverage in each pixel that results from the scan pattern.