Anomalous Microwave Emission (AME) is a component of diffuse Galactic radiation observed at frequencies in the range ≈ 10–60 GHz. AME was first detected in 1996 and recognised as an additional component of emission in 1997. Since then, AME has been observed by a range of experiments and in a variety of environments. AME is spatially correlated with far-IR thermal dust emission but cannot be explained by synchrotron or free–free emission mechanisms, and is far in excess of the emission contributed by thermal dust emission with the power-law opacity consistent with the observed emission at sub-mm wavelengths. Polarization observations have shown that AME is very weakly polarized ( ≲ 1 %). The most natural explanation for AME is rotational emission from ultra-small dust grains (“spinning dust”), first postulated in 1957. Magnetic dipole radiation from thermal fluctuations in the magnetization of magnetic grain materials may also be contributing to the AME, particularly at higher frequencies ( ≳ 50 GHz). AME is also an important foreground for Cosmic Microwave Background analyses. This paper presents a review and the current state-of-play in AME research, which was discussed in an AME workshop held at ESTEC, The Netherlands, June 2016.

中文翻译：

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异常微波发射 (AME) 研究的现状

异常微波发射 (AME) 是在 ≈ 10–60 GHz 范围内观察到的漫反射银河辐射的一个组成部分。AME 于 1996 年首次被检测到，并于 1997 年被确认为排放的附加成分。从那时起，AME 已被一系列实验和各种环境观察到。AME 与远红外热粉尘发射在空间上相关，但不能用同步加速器或自由发射机制来解释，并且远远超过热粉尘发射贡献的发射，其幂律不透明度与观测到的亚-mm 波长。极化观察表明，AME 的极化非常弱 ( ≲ 1 %)。对 AME 最自然的解释是超小尘埃颗粒（“旋转尘埃”）的旋转发射，首次假设于 1957 年。来自磁性颗粒材料磁化热波动的磁偶极子辐射也可能对 AME 有贡献，尤其是在较高频率 (≳ 50 GHz) 下。AME 也是宇宙微波背景分析的重要前景。本文介绍了 AME 研究的回顾和当前进展，该研究在 2016 年 6 月在荷兰 ESTEC 举行的 AME 研讨会上进行了讨论。