Cosmological Simulations of the Formation of Dark Matter Cores and Bulgeless Galaxies

了解塑造星系形成和演化的物理过程是现代天体物理学的一个基本问题。 该项目将在一个完整的冷暗物质（CDM）宇宙学背景下运行高分辨率和物理细节的模拟，研究这个问题，重点是星系中心。 这项工作的重点是CDM模型的预测与观察到的证据之间的三个密切相关的差异，即i）小星系中心的暗物质核心，ii）大部分无凸出矮星，以及iii）存在具有非常小的（伪）凸出。 模拟有三个共同的特点：i）一个简单的物理动机的描述星星的形成，ii）气体外流驱动的能量反馈从超新星和超大质量黑洞，和iii）星星形成淬火紫外光子。 这些模拟将在整个哈勃时间内将星系的内部结构解析到50秒差距。 这种方法将直接将N体模拟中粒子的空间分布和物理特性与真实的星系实际测量的数量联系起来，使用软件来“观察”模型，包括物理效应以及仪器的已知特性，创建真实的人工数据集。该团队已经使用这种方法获得了关于暗物质形成无凸起星系的开创性结果核心，并模拟宇宙学的星系集，同时再现的光度大小的关系，丰富的阻尼莱曼α系统，和HI塔利-费舍尔关系。 这项新工作的具体目标包括了解气体外流如何在星系中心产生暗物质核心，并预测它们在星系质量范围内的大小，合并和星星形成历史，了解星系中心区域气体外流，合并和各种动力学不稳定性对恒星凸起和伪凸起的产生或抑制的作用，以及预测星系中重子质量分布的可观测光度学和运动学性质。PI将与他所在机构资助的天文学专业预科项目（Pre-MAP）合作，该项目帮助代表性不足的学生过渡到大学，并可能进入天文学专业，为他们提供学术咨询和一对一的指导，同时指导他们完成研究项目。 本研究将为MAP预科学生提供研究项目，并为与该计划相关的本科生提供辅导和支持。

ABSTRACTAST-1108885GovernatoUnderstanding the physical processes that shape the formation and evolution of galaxies is a fundamental question in modern astrophysics. This project will run simulations with high resolution and physical detail in a full Cold Dark Matter (CDM) cosmological context, studying this problem with a strong emphasis on galaxy centers. The work focuses on three closely interconnected discrepancies between predictions of the CDM model and the observed evidence for i) dark matter cores at the centers of small galaxies, ii) the large fraction of bulgeless dwarfs, and iii) the existence of massive disk galaxies with very small (pseudo) bulges. The simulations share three common features: i) a simple yet physically motivated description of star formation, ii) gas outflows driven by energy feedback from supernovae and supermassive black holes, and iii) star formation quenching by ultraviolet photons. These simulations will resolve the inner structure of galaxies down to fifty parsecs over the entire Hubble time. This approach will relate directly the spatial distribution and physical properties of the particles in the N-Body simulations to the quantities actually measured for real galaxies, using software to "observe" the models, including physical effects as well as the known properties of instruments, to create realistic artificial datasets.This team has already used this approach to obtain seminal results on the formation of bulgeless galaxies with dark matter cores, and to simulate a cosmological set of galaxies that simultaneously reproduce the luminosity-size relation, the abundance of damped Lyman alpha systems, and the HI Tully-Fisher relation. Specific goals of this new work include understanding how gas outflows create dark matter cores at the centers of galaxies and predicting their size over a range of galaxy masses and merging and star formation histories, understanding the role of gas outflows, mergers and various dynamical instabilities in the central region of galaxies on the creation or suppression of stellar bulges and pseudo bulges, and predicting the observable photometric and kinematic properties of the baryonic mass distribution in galaxies.The PI will collaborate with his institution's funded Pre-Major in Astronomy Program (Pre-MAP), which helps underrepresented students in their transition to college and possibly to an astronomy major, providing them with academic advising and one to one mentorship while guiding them through research projects. The present study will provide research projects for Pre-MAP students and tutoring and support for undergraduates linked to the program.