High-Resolution Simulations of Galaxy and Cluster Formation: Towards a Self-Consistent Modelling of Stellar Feedback

AST 0206216Kravtsov现代天体物理学最大的挑战之一是理解像我们银河系这样的星系是如何在大爆炸宇宙学的框架内形成的。目前的结构形成理论（称为冷暗物质（CDM）方案）预测，大质量星系是由较小的星系碰撞和合并而成的，引发了星星形成的爆发，并导致了今天观察到的不同类型的星系。 这整个事件序列被认为是由非常早期宇宙中的量子波动所引发的，并由神秘的“暗物质”所控制，暗物质占宇宙中所有物质的85%。 虽然CDM理论成功地解释了许多观测结果，但它面临着越来越多的问题，这些问题可能会导致我们修改甚至放弃这一范式。一个根本的、尚未解答的问题是，是否可以形成具有与观测星系相似性质的现实星系CDM模型。该项目将特别侧重于恒星反馈和重元素富集及其在星系演化中的作用。Kravtsov博士和他的合作者将通过使用非常高分辨率，最先进的计算机模拟来解决这个问题，其中包括所有被认为在星系中重要的主要过程。特别是，这些模拟将解释年轻大质量恒星爆炸时释放到周围气体中的巨大能量和重元素。这种能量释放，或称“反馈”，被认为在控制星际气体转化为恒星的速度和塑造星系的整体性质方面起着关键作用。***

AST 0206216KravtsovOne of the greatest challenges of modern astrophysics is understanding how galaxies such as our own Milky Way form within the framework of the Big Bang cosmology. The current theory of structure formation (called the Cold Dark Matter (CDM) scenario) predicts that massive galaxies were built from smaller galaxies that collided and merged, inducing bursts of star formation and resulting in the different types of galaxies observed today. This entire sequence of events is thought to be seeded by quantum fluctuations in the very early Universe and governed by mysterious "dark matter" which constitutes about 85% of all matter in the universe. While the CDM theory is successful in explaining many observations, it faces an increasing number of problems which may lead us to revise or even abandon this paradigm.One of the fundamental, unanswered questions is whether realistic galaxies with properties similar to those of observed galaxies can be formed in the CDM model. This project will specifically focus on stellar feedback and heavy element enrichment and their role in the evolution of galaxies. Dr. Kravtsov and his collaborators will address this question by using very high-resolution, state-of-the-art computer simulations which include all the main processes thought to be important in galaxy. In particular, the simulations will account for the release of enormous amounts of energy and heavy elements into the surrounding gas by the explosions of young, massive stars. This energy release, or "feedback", is thought to play a critical role in controlling the rate at which interstellar gas is turned into stars and in shaping the overall properties of galaxies. ***