论文标题
发现天空中最难以捉摸的无线电遗物：该法案中遇到的弥漫性冲击加速度？
Discovering the most elusive radio relic in the sky: Diffuse Shock Acceleration caught in the act?
论文作者
论文摘要
无线电遗物的起源通常是通过在星系簇中的合并冲击中/从合并冲击中进行的扩散冲击加速器（DSA）或重新加速的。加速度的案例受到低模数合并冲击的预测效率低的质疑，无法解释大多数无线电遗物中观察到的能力。在这封信中，我们介绍了使用Lofar的Galaxy Cluster Abell 2249（$ Z = 0.0838 $）围绕Galaxy Cluster Abell 2249（$ Z = 0.0838 $）的发现。这很特别，因为它具有所有已知无线电文物的表面亮度最低。我们研究其无线电和X射线特性与UGMRT，JVLA和XMM组合。该对象的总功率为$ l_ {1.4 \ rm ghz} = 4.1 \ pm 0.8 \ times 10^{23} $ w hz $^{ - 1} $和集成的频谱索引$α= 1.15 \ pm 0.23 $。我们为此无线电遗物推断出$ b \ geq 0.4 \，μ$ g的磁性下限，$ \ mathcal {m} \大约3.79 $的冲击马赫数和与DSA一致的低加速度效率。该结果表明，由于新一代射电望远镜的前所未有的敏感性，遗物遗失的遗物可能变得可见。
The origin of radio relics is usually explained via diffusive shock acceleration (DSA) or re-acceleration of electrons at/from merger shocks in galaxy clusters. The case of acceleration is challenged by the low predicted efficiency of low-Mach number merger shocks, unable to explain the power observed in most radio relics. In this Letter we present the discovery of a new giant radio relic around the galaxy cluster Abell 2249 ($z=0.0838$) using LOFAR. It is special since it has the lowest surface brightness of all known radio relics. We study its radio and X-ray properties combinig LOFAR data with uGMRT, JVLA and XMM. This object has a total power of $L_{1.4\rm GHz}=4.1\pm 0.8 \times 10^{23}$ W Hz$^{-1}$ and integrated spectral index $α= 1.15\pm 0.23$. We infer for this radio relic a lower bound on the magnetisation of $B\geq 0.4\, μ$G, a shock Mach number of $\mathcal{M}\approx 3.79$, and a low acceleration efficiency consistent with DSA. This result suggests that a missing population of relics may become visible thanks to the unprecedented sensitivity of the new generation of radio telescopes.
