Espresso and Stochastic Acceleration of Ultra-high-energy Cosmic Rays in Relativistic Jets
Espresso and Stochastic Acceleration of Ultra-high-energy Cosmic Rays in Relativistic Jets
复制标题
相对论射流中超高能宇宙射线的浓缩咖啡和随机加速
DOI：
10.3847/1538-4357/ac1da8
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
D. Caprioli
中科院分区：
文献类型：
--
作者：
R. Mbarek;D. Caprioli
在浓缩咖啡的情况下，超高能（UHE）宇宙射线（CR）是通过活动星系核的相对论喷流中的类银河宇宙射线的一次性再加速产生的，与磁场波动所决定的散射率无关。在Mbarek & Caprioli（2019）中，我们在高分辨率磁流体动力学（MHD）射流模拟中追踪了测试粒子CR，并发现相关的光谱斜率，化学成分和各向异性与UHECR现象学一致。在这项工作中，我们扩展了这样的分析，包括亚网格俯仰角散射模型的小尺度磁湍流，不能解决的MHD模拟。我们发现，一个大的散射率解锁随机加速度，并促进低能量CR，这最终导致更硬的UHECR光谱。然而，达到最高能量（达到希拉斯极限）的粒子总是由浓咖啡加速产生的，它们的光谱与假设的亚网格散射率无关。
In the espresso scenario, ultra-high-energy (UHE) cosmic rays (CRs) are produced via a one-shot reacceleration of galactic-like CRs in the relativistic jets of active galactic nuclei, independently of the scattering rate dictated by magnetic fluctuations. In Mbarek & Caprioli (2019) we traced test-particle CRs in high-resolution magnetohyrodynamic (MHD) jet simulations and found that the associated spectral slope, chemical composition, and anisotropy are consistent with UHECR phenomenology. In this work, we extend such an analysis by including subgrid pitch-angle scattering to model small-scale magnetic turbulence that cannot be resolved by MHD simulations. We find that a large scattering rate unlocks stochastic acceleration and fosters the energization of lower-energy CRs, which eventually leads to harder UHECR spectra. Yet, the particles that achieve the highest energies (up to the Hillas limit) are invariably produced by espresso acceleration and their spectrum is independent of the assumed subgrid scattering rate.
DOI：
10.3847/1538-4357/aa7410
发表时间：
2017-06
期刊：
The Astrophysical Journal
影响因子：
--
作者：
Ruo-Yu Liu;F. Rieger;F. Aharonian
通讯作者：
Ruo-Yu Liu;F. Rieger;F. Aharonian
FR0 射电星系的高分辨率 VLA 观测：紧凑射电源的特性和性质
影响因子：
4.8
作者：
Baldi R
通讯作者：
Baldi R