Observations of radio relics at very high frequency (>10 GHz) can help to understand how particles age and are (re-)accelerated in galaxy cluster outskirts and how magnetic fields are amplified in these environments. In this work, we present new single-dish 18.6 GHz Sardinia Radio Telescope and 14.25 GHz Effelsberg observations of the well known northern radio relic of CIZA J2242.8+5301. We detected the relic which shows a length of $\sim$1.8 Mpc and a flux density equal to $\rm S_{14.25\,GHz}=(9.5\pm3.9)\,mJy$ and $\rm S_{18.6\,GHz}=(7.67\pm0.90)\,mJy$ at 14.25 GHz and 18.6 GHz respectively. The resulting best-fit model of the relic spectrum from 145 MHz to 18.6 GHz is a power-law spectrum with spectral index $\alpha=1.12\pm0.03$: no evidence of steepening has been found in the new data presented in this work. For the first time, polarisation properties have been derived at 18.6 GHz, revealing an averaged polarisation fraction of $\sim40\%$ and a magnetic field aligned with the 'filaments' or 'sheets' of the relic.

中文翻译：

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CIZA J2242.8+5301 北方无线电遗迹的光谱极化观测：没有高频陡峭的证据

以非常高的频率（> 10 GHz）观察无线电遗迹可以帮助了解粒子如何老化和在星系团外围（重新）加速，以及磁场如何在这些环境中被放大。在这项工作中，我们展示了新的单碟 18.6 GHz 撒丁岛射电望远镜和 14.25 GHz Effelsberg 对著名的北方射电遗迹 CIZA J2242.8+5301 的观测。我们检测到的遗迹显示长度为 $\sim$1.8 Mpc，通量密度等于 $\rm S_{14.25\,GHz}=(9.5\pm3.9)\,mJy$ 和 $\rm S_{18.6\ ,GHz}=(7.67\pm0.90)\,mJy$ 分别在 14.25 GHz 和 18.6 GHz。从 145 MHz 到 18.6 GHz 的残余频谱的最终最佳拟合模型是具有频谱指数 $\alpha=1.12\pm0.03$ 的幂律频谱：在本报告中提供的新数据中没有发现陡峭的证据工作。首次，