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arXiv 1909.00261astro-ph.HEastro-ph.GA
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超高能cosmic ray源射电星系的参数化星表

A parameterized catalog of radio galaxies as ultra-high energy cosmic ray sources

Jörg P. Rachen, Björn Eichmann

摘要:

人们已经做出了许多尝试,以提供基于各种天文示踪剂的超高能宇宙射线(UHECR)粒子的潜在来源目录,例如观测到的无线电或伽马射线发射。然而,仔细观察就会发现,它们都受到明显的偏见和选择效应的影响。我们在这里提出了一个演示版本的目录经常讨论的UHECR源类,射电星系(或射电响亮AGN),这是基于一个完整的理论描述的喷流能量,粒子加速物理,相对论光束效应和核成分,参数化的一组可调的物理量。除了明亮的射电星系半人马座A,室女座A,天炉座A和天鹅座A在以前的工作中讨论,我们发现几个源与耀变体的属性,可以在类似的水平上,如果考虑相对论光束效应的贡献。我们提出了一个简单的方法来测试的基本属性的目录的任何选择的参数(而不需要运行昂贵的模拟),并发现,在典型的情况下,预计从射电星系的各向异性信号的承诺是在良好的协议与目前的观测结果。特别是,如果我们假设河外磁场仅在结构中很强(>1nG),但在空洞中很弱,那么射电星系几乎可以精确地再现皮埃尔·俄歇天文台探测到的8 EeV以上的偶极子方向。我们计划以电子形式提供此目录的完整和改进版本,用于更详细的UHECR传播模拟。对于直接的应用,我们建议一套完整的16强UHECR源,可以有助于UHECR各向异性的水平上,目前可以通过实验探测,并注意到,其中6个没有被认为是在任何以前的研究。

英文摘要:

Many attempts have been made to provide catalogs of potential sources of ultra-high energy cosmic ray (UHECR) particles based on various astronomical tracers, such as observed radio or gamma-ray emission. A closer look reveals, however, that they all suffer from significant bias and selection effects. We present here a demo-version of a catalog for one often-discussed UHECR source class, radio galaxies (or radio-loud AGN), which is based on a complete theoretical description of jet-energetics, particle acceleration physics, relativistic beaming effects and nuclear composition, parametrized by a comprehensible set of adjustable physical quantities. In addition to the bright radio galaxies Centaurus A, Virgo A, Fornax A and Cygnus A discussed in previous work, we find several sources with blazar-like properties that can contribute on a similar level if relativistic beaming effects are considered. We present a simple method to test the basic properties of the catalog for any choice of parameters (without the need to run expensive simulations), and find that in the canonical case the anisotropy signals expected from radio galaxies promise to be in good agreement with current observational findings. In particular, radio galaxies can reproduce almost exactly the direction of the dipole above 8 EeV detected by the Pierre Auger Observatory if we assume that extragalactic magnetic fields are strong (>1nG) only in structures, but very weak in voids. We plan to provide a completed and improved version of this catalog in electronic form, to be used in more detailed UHECR propagation simulations. For immediate applications, we suggest a complete set of 16 strong UHECR sources which can contribute to UHECR anisotropy on the level which can be currently probed by experiment, and note that 6 of them have not been considered in any previous studies.

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