Integrating precision observations and simulations of the Intergalactic Medium

星际介质是宇宙的大部分体积，直到最近，它还包含了大部分暗物质和气体。这个项目是通过类星体光谱中的吸收对星际介质进行精确测量的紧密结合，以及一套旨在从这些测量中提取物理参数的模拟。它将提供对宇宙学感兴趣的参数的新估计，包括重子、暗物质和暗能量含量，以及小尺度上的物质聚集量，这些参数比以前从星际气体获得的参数更准确，并且完全独立于来自超新星、星系和宇宙微波背景的参数。对于所有参数，误差将与任何方法中最好的方法相媲美。这项工作还将对星际气体的温度和紫外线背景辐射的强度进行更准确的测量。复杂的光谱校准将使它们适合于确定哪组参数使模拟光谱最接近真实光谱。一些模拟将包括辐射传输，以解释接近单个类星体的吸收。这个团队在将教育和多样性与他们的研究相结合方面有着长期的记录。学生们接受天体物理学、宇宙学和精密测量方法的密集指导，使用Keck和Lick望远镜进行观察，并学习在最先进的超级计算机上运行大型代码。大多数本科生也将成为一到两篇论文的共同作者。

AST-0808168TytlerThe intergalactic medium is most of the volume of the Universe and until recently it contained most of the dark matter and gas. This project is a tight combination of precision measurements of the intergalactic medium through absorption in quasar spectra with a suite of simulations designed to extract the physical parameters from those measurements. It will provide new estimates of cosmologically interesting parameters, including the baryonic, dark matter and dark energy contents, and the amount of clustering of matter on small scales, which are more accurate than those obtained before from the intergalactic gas, and completely independent of those from supernovae, galaxies and the cosmic microwave background. For all parameters the errors will be comparable to the best of any method. The work will also give much more accurate measurements of the temperature of the intergalactic gas, and the intensity of the ultraviolet background radiation. Sophisticated calibrations of spectra will make them suitable for determining which set of parameters makes the simulated spectra most like the real spectra. Some simulations will include radiative transfer so as to interpret absorption near to individual quasars.This team has a long record of integrating education and diversity with their research. Students receive intensive instruction in astrophysics, cosmology and the methods of precision measurement, observing with the Keck and Lick telescopes, and learn to run a large code on state-of-the-art supercomputers. Most undergraduates will also become co-authors on one or two papers.