用POLARBEAR测量宇宙微波背景循环偏振的半波板的表征
T Fujino1, S Takakura2, Y Chinone3,4
1Graduate School of Engineering Science, Yokohama National University, Yokohama 240-8501, Japan.
The Review of scientific instruments
|October 20, 2023
概括
一个半波板 (HWP) 可以测量宇宙微波背景圆极化 (CP),这对于检测早期宇宙现象,如人口III恒星至关重要. 这项研究量化了HWP.
科学领域:
- 宇宙学和天体物理学
- 对于CMB观测的仪器开发.
背景情况:
- 半波板 (HWPs) 是减少宇宙微波背景 (CMB) 偏振测量系统错误的必要调节器.
- 高功率电池还可以通过光学泄漏将其转换为线性极化来检测循环极化 (CP).
- 圆形极化CMB是一个与早期宇宙物理学和标准模型的扩展相关的预测现象.
研究的目的:
- 为了证明对CP检测的HWP泄漏系数的改进测量.
- 评估CMB CP观测的潜力,以识别群体III恒星,预测一个明亮的CP源.
- 为了评估北极熊实验的CP灵敏度.
主要方法:
- 在120-160 GHz频率范围内通过实际的HWP (在北极熊中使用) 测量了线性极化光的透射率.
- 将实验数据与使用马尔科夫链蒙特卡洛 (MCMC) 方法评估HWP属性的物理模型相匹配.
- 估计了带平均CP泄漏系数,考虑到探测器带宽和潜在的系统效应.
主要成果:
- 发现HWP泄漏系数在很大程度上取决于CP源的光谱.
- 从CP到线性偏振的最大分数泄漏系数被确定为0.133±0.009对于雷利-吉恩斯光谱.
- 不同于零的泄漏系数证实了北极熊实验对CMB循环偏振的敏感性.
结论:
- 该研究成功量化了HWP的CP泄漏系数,验证了其用于CP测量的能力.
- 这些发现表明,CMB循环极化观测得到HWPs的帮助,为寻找群体III恒星提供了一种新的方法.
- 结果证实了北极熊实验对循环偏振的敏感性,有助于CMB观测宇宙学的进步.
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