河外极高能宇宙线的起源  

The origin of extragalactic ultrahigh energy cosmic rays

作　　者：柳若愚[1] 王祥玉[1] 张冰[2,3] 

机构地区：[1]南京大学天文与空间科学学院,南京210046 [2]北京大学物理学院天文系及科维里天文与天体物理研究所,北京100871 [3]美国内华达大学拉斯维加斯分校物理天文系

出　　处：《中国科学：物理学、力学、天文学》2015年第11期100-125,共26页Scientia Sinica Physica,Mechanica & Astronomica

基　　金：国家重点基础研究发展规划(批准号:2014CB845800);国家自然科学基金(批准号:11273016)资助项目

摘　　要：由于大型宇宙线探测器Pierre Auger,Telescope Array等的观测,极高能宇宙线(能量大于1018 e V的宇宙线)的研究取得了很大进展,包括探测到高能能谱变陡,与河外天体源的可能相关性,以及化学成分组成等.然而这些宇宙线的起源天体仍未知.本文将评述河外极高能宇宙线起源的候选天体,包括伽玛射线暴,活动星系核,巨超新星等.同时我们从多信使角度(包括高能中微子,伽玛光子的观测),探讨这些天体是河外极高能宇宙线起源天体的可能性.The origin of ultrahigh energy cosmic rays is a long-standing puzzle. Studies on these energetic particles will not only reveal the most violent process in the universe, but also extend our understanding on particle physics at extremely high energies. Thanks to large cosmic ray experiments such as the Pierre Auger Observatory （PAO） and the Telescope Array （TA）, a lot of progress has been made in the studies on cosmic rays with energy above 10^18eV, including the discovery of flux suppression at the highest energy of the spectrum or the GZK cutoff, the possible anisotropy signal especially the correlation with extragalactic objects and their chemical compositions. In this paper, we firstly give a brief review on the detection technique of ultrahigh energy cosmic rays and recent results from PAO and TA. And then, various candidate sources of ultrahigh energy cosmic rays such as gamma-ray bursts, active galactic nuclei, intergalactic shocks are introduced, as well as some basic theories on particle acceleration mechanisms. Also, we discuss the interactions of ultrahigh energy cosmic rays with photon fields, matter and magnetic fields. Some constraints on candidate sources can be obtained through multi-messengers like high energy neutrinos and gamma rays generated in the propagation of the cosmic rays from distant universe. Additionally, the possible anisotropy signal of ultrahigh energy cosmic ray events can also be used to study the distance and metallicity of the candidate sources, and probe Galactic and extragalactic magnetic fields.

关 键 词：粒子天体物理 极高能宇宙线 中微子 伽玛射线 磁场 

分 类 号：P172.4[天文地球—天文学]