Evidence for the re-ionization of He II from the evolution of the Ly-alpha forest optical depth in the SDSS?

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。 Bernardi博士将使用比以前更大的样本继续她对莱曼-阿尔法森林中光学深度演变的研究。 过去的工作表明，红移为3.2的光学深度的急剧变化很可能是由于He II的再电离。这里将要进行的工作将试图使用来自斯隆数字巡天数据第7版的更大数据集来巩固这一结论。 这些数据还将用于研究再电离的斑块，这将对电离光子起源的模型产生约束。 这一努力的更广泛影响包括培训一名研究生。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). Dr. Bernardi will continue her investigations of the evolution of the optical depth in the Lyman-Alpha Forest using a much larger sample than previously available. Past work has shown that a sharp change in optical depth at a redshift of 3.2 is very likely due to He II reionization. The work to be carried out here will attempt to solidify this conclusion using a much larger dataset derived from the Sloan Digital Sky Survey Data Release 7. The data will also be used to study the patchiness of reionization, which will place constraints on models for the origin of the ionizing photons. Broader impacts of this effort include training of a graduate student.