Current and future Cosmic Microwave Background (CMB) Radiation experiments are targeting the polarized $B$-mode signal. The small amplitude of this signal makes a successful measurement challenging for current technologies. Therefore, very accurate studies to mitigate and control possible systematic effects are vital to achieve a successful observation. An additional challenge is coming from the presence of polarized Galactic foreground signals that contaminate the CMB signal. When they are combined, the foreground signals dominate the polarized CMB signal at almost every relevant frequency. Future experiments, like the LiteBIRD space-borne mission, aim at measuring the CMB $B$-mode signal with high accuracy to measure the tensor-to-scalar ratio $r$ at the $10^{-3}$ level. We present a method to study the photometric calibration requirement needed to minimize the leakage of polarized Galactic foreground signals into CMB polarization maps for a multi-frequency CMB experiment. We applied this method to the LiteBIRD case, and we found precision requirements for the photometric calibration in the range $\sim10^{-4}-2.5\times10^{-3}$ depending on the frequency band. Under the assumption that the detectors are uncorrelated, we found requirements per detector in the range $\sim0.18\times10^{-2}-2.0\times10^{-2}$. Finally, we relate the calibration requirements to the band-pass resolution to define constraints for a few representative band-pass responses: $\Delta\nu\sim0.2-2$ GHz.

中文翻译：

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未来CMB卫星任务的要求：光度和带通响应校准

当前和未来的宇宙微波背景 (CMB) 辐射实验都针对极化的 $B$ 模式信号。该信号的小幅度使得成功测量对当前技术具有挑战性。因此，减轻和控制可能的系统影响的非常准确的研究对于实现成功的观察至关重要。另一个挑战来自会污染 CMB 信号的极化银河前景信号。当它们组合在一起时，前景信号在几乎每个相关频率上都支配着极化的 CMB 信号。未来的实验，如 LiteBIRD 星载任务，旨在高精度测量 CMB $B$ 模式信号，以测量 $10^{-3}$ 水平的张量标量比 $r$。我们提出了一种方法来研究将偏振银河前景信号泄漏到 CMB 偏振图中以进行多频 CMB 实验所需的光度校准要求。我们将此方法应用于 LiteBIRD 案例，我们发现光度校准的精度要求在 $\sim10^{-4}-2.5\times10^{-3}$ 范围内，具体取决于频段。在检测器不相关的假设下，我们发现每个检测器的要求在 $\sim0.18\times10^{-2}-2.0\times10^{-2}$ 范围内。最后，我们将校准要求与带通分辨率联系起来，以定义几个有代表性的带通响应的约束条件：$\Delta\nu\sim0.2-2$ GHz。我们将此方法应用于 LiteBIRD 案例，我们发现光度校准的精度要求在 $\sim10^{-4}-2.5\times10^{-3}$ 范围内，具体取决于频段。在检测器不相关的假设下，我们发现每个检测器的要求在 $\sim0.18\times10^{-2}-2.0\times10^{-2}$ 范围内。最后，我们将校准要求与带通分辨率联系起来，以定义几个有代表性的带通响应的约束条件：$\Delta\nu\sim0.2-2$ GHz。我们将此方法应用于 LiteBIRD 案例，我们发现光度校准的精度要求在 $\sim10^{-4}-2.5\times10^{-3}$ 范围内，具体取决于频段。在检测器不相关的假设下，我们发现每个检测器的要求在 $\sim0.18\times10^{-2}-2.0\times10^{-2}$ 范围内。最后，我们将校准要求与带通分辨率联系起来，以定义几个有代表性的带通响应的约束条件：$\Delta\nu\sim0.2-2$ GHz。