Cosmological evolution and very high energy astrophysics

该奖项是根据2009年《美国复苏和再投资法案》(公法111-5)提供资金的。该项目的工作将致力于研究宇宙射线源的宇宙学演化和河外光线背景。目前还远不清楚哪个是UHECR源宇宙学演化的最佳代表，因为我们不确定这些源是什么。因此，PI将尝试结合不同的超高和超高能实验的信息，包括(希望)未来对超高能中微子的探测，并得出与宇宙学演化有关的结论。PI提出的理论工作和数据分析将导致更好地了解不同类型的强大河外宇宙源的宇宙学演化，并识别超高能宇宙射线(UHECR)的来源--宇宙中最高能量的原子核。将特别关注不同类型可能来源的宇宙学演化。这一演化的分辨率决定了宇宙光子场中超高能宇宙射线相互作用产生的宇宙伽马射线和中微子的二次通量的产生。这包括红外、光学和紫外线范围内的微波背景光和河外背景光(EBL)。EBL在宇宙成因通量的产生和对TeV伽马射线的吸收中起着重要作用--既有宇宙成因的伽马射线，也有来自不同河外来源的伽马射线。对来自不同来源的伽马射线吸收的比较可能会揭示目前存在争议的EBL的宇宙学演化。拟议的工作结果将产生关于更广泛的全球天体物理和宇宙学参数的信息，这突显了这项工作的更广泛的影响。PI是埃赖斯国际宇宙线天体物理学校(ISCRA)的联席主任，并在那里为年轻科学家讲课。该学院每两年举行一次会议，平均有60名学生(研究生和博士后)和12名讲师。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). The work on this project will be dedicated to studies of the cosmological evolution of the cosmic ray sources and of the extragalactic light background. It is currently far from obvious which is the best proxy for the cosmological evolution of the UHECR sources since we are not certain what the sources are. The PI will thus attempt to combine the information from different ultra high and very high energy experiments, including (hopefully) the future detection of very high energy neutrinos, and reach conclusions related to cosmological evolution. The PI proposes theoretical work and data analysis that will lead to a better understanding of the cosmological evolution of different types of powerful extragalactic sources and to identification of the sources of ultrahigh energy cosmic rays (UHECR) - the highest energy nuclei in the Universe. Special attention will be paid to the cosmological evolution of different types of possible sources. The resolution of this evolution dominates the production of secondary fluxes of cosmogenic gamma rays and neutrinos from ultra high energy cosmic rays interactions in the universal photon fields. These include the microwave background and the extragalactic background light (EBL) in infrared, optical and UV ranges. EBL plays important role in the production of the cosmogenic fluxes and in the absorption of TeV gamma rays - both cosmogenic ones as well as of those coming from different extragalactic sources. The comparison of the absorption of the gamma rays coming from different sources may reveal the cosmological evolution of EBL that is now being disputed.The results of the proposed work will yield information about a much wider range of global astrophysical and cosmological parameters which underscores the broader impact of this work. The PI is Co-Director of the Erice International School for Cosmic Rays Astrophysics (ISCRA) and gives lectures there to young scientists. The School meets every two years and has on the average 60 students (graduate students and postdocs) and 12 lecturers.