One of the main goals of most future CMB experiments is the precise measurement of CMB B-mode polarization, whose major obstacle is the Galactic foregrounds. In this paper, we evaluate the foreground cleaning performance of the variants of the ILC method on partial sky B-modes and analyze the main sources of biases on the BB power spectrum. Specially, we compare the NILC, the cILC (in three domains) and the cMILC methods for AliCPT-1 simulations. We find that the cILC methods implemented in harmonic space and needlet space are both competent to clean different models of foregrounds, which bias the tensor-to-scalar ratio about 0.008 at maximum, and constrain the tensor-to-scalar ratio to r < 0.043(95%CL) for the AliCPT-1 configuration. We also note that the deviation of the estimated noise bias from the actual one for ILC, dubbed the noise bias error (NBE) in this paper, might make significant effects on the power spectrum for a small footprint and low signal-to-noise ratio CMB experiment. We finally obtain its relation with respect to the noise residual which fits well with the simulated results.

中文翻译：

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AliCPT-1 使用 ILC 方法去除前景

未来大多数 CMB 实验的主要目标之一是精确测量 CMB B 模式偏振，其主要障碍是银河系前景。在本文中，我们评估了 ILC 方法变体在部分天空 B 模式上的前景清洁性能，并分析了 BB 功率谱偏差的主要来源。特别是，我们比较了 AliCPT-1 模拟的 NILC、cILC（在三个领域）和 cMILC 方法。我们发现在调和空间和针状空间中实现的 cILC 方法都能够清理不同的前景模型，这使得张量与标量之比最大偏置约 0.008，并将张量与标量之比限制为r对于 AliCPT-1 配置，< 0.043(95%CL)。我们还注意到，ILC 的估计噪声偏差与实际噪声偏差（在本文中称为噪声偏差误差 (NBE)）可能会对小封装和低信噪比的功率谱产生重大影响宇宙微波背景辐射实验。我们最终得到了它与噪声残差的关系，与模拟结果非常吻合。