International Research Fellow Awards Program: Development of a State-of-the-art Three-dimensional Cosmological Gas Dynamics and Radiation Dynamics Code

国际研究员奖励计划使美国科学家和工程师能够在国外进行三到二十四个月的研究。该计划的奖项提供了联合研究的机会，并利用国外独特或互补的设施、专业知识和实验条件。该奖项将为伊利安·T·伊利耶夫博士提供六个月的支持，以便与墨西哥墨西哥城国家自治大学的亚历杭德罗·C·拉加博士合作。这个项目是由美国国家科学基金会数学和物理科学局的多学科活动办公室共同资助的。从宇宙只有100万年的重组时代到10亿年或更长时间后第一个类星体的出现之间的一段时间，宇宙中的大多数物质再次被电离。通过使用数值模拟来模拟这个再电离时代，PI将致力于回答这样的问题：什么类型的物体在什么时候重新电离了宇宙？第一批天体(恒星、原星系)是何时形成的，又是如何形成的？紫外光电离背景是如何演化的？这种背景对后来形成的物体有什么影响？该项目要求开发最先进的三维宇宙气体动力学和辐射动力学程序，以详细研究这些关于我们今天看到的宇宙结构的起源和演化的重要问题。他们希望深入研究宇宙电离过程中的过程，以及反馈和辐射转移对宇宙结构形成的影响。宇宙学的这个领域关注的是理解我们所看到的宇宙中所有的结构是如何形成和演化的。拉加和他的合作者开发了一种星际气体和辐射动力学代码，该代码将被进一步开发，以包括自引力的影响，使其适用于宇宙学模拟。

00003682IlievThe International Research Fellow Awards Program enables U.S. scientists and engineers to conduct three to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad.This award will provide Dr. Ilian T. Iliev with support for six months to work with Dr. Alejandro C. Raga at Universidad Nacional Autonoma de Mexico in Mexico City, Mexico. This project is being co-funded by NSF's Directorate for Mathematical and Physical Sciences' Office of Multidisciplinary Activities.Sometime between the recombination epoch when the universe was only a million years old, and the appearance of the first quasars a billion years or more later, most matter in the universe became ionized again. By using numerical simulations to model this reionization epoch the PIs will work to answer the questions: What kind of objects reionized the universe and when? When and how did the first objects (stars, protogalaxies) form? How did the photoionizing ultraviolet background evolve? What was the impact of this background on the objects forming later? The project calls for development of state-of-the-art three-dimensional cosmological gas dynamics and radiation dynamics code to study in detail these important questions about the origin and evolution of the cosmic structures we see today. They expect to conduct an in-depth study of the processes during the reionization of the universe and the effects of feedback and radiative transfer on the formation of cosmic structures. This area of cosmology is concerned with understanding how all the structures in the universe we see are formed and evolved.Dr. Raga and his collaborators have developed an interstellar gas-and radiation dynamics code, which will be further developed to include the effects of self-gravity, adapting it for cosmological simulations.