COLLABORATIVE RESEARCH: New Frontiers in Galaxy Formation Modeling

了解星系的形成是现代宇宙学中最重要和最具挑战性的问题之一。特别是，恒星形成可能是现代宇宙学模拟中最不为人所知和最不发达的成分。这个由Kravtsov博士领导的合作项目，旨在通过开发新的、由观测驱动的恒星和星团形成模型，大大减少星系形成物理学中的不确定性。数值算法和计算能力的最新进展意味着宇宙学流体动力学模拟现在可以解决星际介质中恒星形成的实际位置，从而有可能自一致地跟踪巨大分子云的形成和破坏。计划中的超高分辨率n体和气体动态自适应网格细化模拟将包含前所未有的丰富的物理过程，包括尘埃上分子氢的形成及其对环境紫外线辐射的自屏蔽，以及自一致的三维连续辐射传输。在较小的未解决的尺度上，模拟将结合基于可靠的经验相关性的恒星形成配方。计划中的研究将研究高红移星系的分子含量，制定符合观测相关性的恒星形成处方，并研究不同星系环境下的恒星形成。它将解决存在丰富观测数据的大质量星团的形成和演化问题，并研究星团形成效率与宿主星系性质的依赖关系。这个项目的独特之处在于它能够在大尺度星系形成和小尺度恒星形成之间架起桥梁，从而在这两个研究团体之间建立联系。通过让学生参与进来，这项工作为年轻的计算宇宙学家提供了尖端模拟技术的专业培训。这些结果为当前和即将到来的空间和地面观测计划提供了支持。研究成果与学术教学、公共教育和推广活动紧密结合。模拟的三维可视化将可用于天文馆展览和公共讲座，也可在网上访问。

AST-0708154/0708087Kravtsov/GnedinUnderstanding galaxy formation is one of the most important and challenging problems in modern cosmology. In particular, star formation is perhaps the worst understood and least developed ingredients of modern cosmological simulations. This collaborative project, led by Dr Kravtsov, aims to reduce greatly the uncertainty in the physics of galaxy formation by developing new, observationally motivated models for the formation of stars and star clusters. Recent advances in numerical algorithms and computing power mean that cosmological hydrodynamical simulations can now resolve the actual sites of star formation in the interstellar medium, making it possible to track the formation and destruction of giant molecular clouds self-consistently. The planned suite of ultra high-resolution N-body and gas dynamic adaptive mesh refinement simulations will incorporate an unprecedented wealth of physical processes, including the formation of molecular hydrogen on dust and its self-shielding from ambient ultraviolet radiation, and self-consistent three-dimensional continuum radiative transfer. On smaller unresolved scales, the simulations will incorporate star formation recipes based on reliable empirical correlations. The planned research will study the molecular content of high-redshift galaxies, develop star formation prescriptions consistent with the observational correlations, and study star formation in different galactic environments. It will address the formation and evolution of massive star clusters, for which abundant observational data exist, and investigate the dependence of cluster formation efficiency on properties of the host galaxy.This project is unique in its ability to bridge the large scales of galaxy formation and the small scales of star formation, thus developing links between those two research communities. By involving students, the work provides professional training of young computational cosmologists in cutting-edge simulation techniques. The results provide support for current and forthcoming space- and ground-based observing programs. The research results are tightly integrated into academic teaching, and public education and outreach activities. Three-dimensional visualizations of the simulations will be available for planetarium shows and public lectures, and also web-accessible.