Integrating precision observations and simulations of the Intergalactic Medium

星系间介质占据了宇宙的大部分体积，直到最近，它还包含了大部分的暗物质和气体。这个项目是通过类星体光谱的吸收对星系间介质的精确测量与一套旨在从这些测量中提取物理参数的模拟的紧密结合。它将提供宇宙学上有趣的参数的新估计，包括重子、暗物质和暗能量的含量，以及小尺度上物质聚集的数量，这些数据比以前从星系间气体中获得的数据更准确，并且完全独立于超新星、星系和宇宙微波背景的数据。对于所有参数，误差将与任何方法中的最佳误差相媲美。这项工作还将对星系间气体的温度和紫外线背景辐射的强度进行更精确的测量。复杂的光谱校准将使它们适合于确定哪一组参数使模拟光谱最接近真实光谱。一些模拟将包括辐射转移，以便解释靠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悠久的历史。学生们在天体物理学、宇宙学和精密测量方法方面接受密集的指导，用凯克和利克望远镜进行观测，并学习在最先进的超级计算机上运行大型代码。大多数本科生也会成为一到两篇论文的合著者。

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.