CAREER: Numerical Simulations of Reionization

建议ID：AST 0134373机构：科罗拉多大学博尔德分校Gnedin获得了科罗拉多大学博尔德分校的资金，以进一步开发模拟早期宇宙第一次再电离的新方法。目前关于宇宙背景辐射的数据表明，从红移约1000的复合时间到红移约20的时间，宇宙中的气体含量基本上保持中性。对红移约为6的类星体的观测表明，当时星系间介质处于高度电离状态。因此，这种“再电离”，即星系间气体从主要中性到主要电离的转变，一定发生在红移为6到20的时间之间。格内丁博士将对模拟辐射传递的数值方法进行重大改进，以期实现数值收敛。这些模型将首次能够对星际介质的演化做出定量准确的预测。格内丁博士将进一步将模型结果与“莱曼破裂星系”进行比较，这是一些最原始的观测星系，试图了解它们的形成。格内丁将通过为非科学专业的学生开发一门新的宇宙学本科课程，以及开发基于网络的普通天文学入门课程的宇宙学部分，来整合他的教学和研究。这项基于网络的工作将包括从他的研究中提取的原始模拟。他还将与本科生专业合作，开发一种新的宇宙学天文表演。

AST- 0134373Nickolay GnedinProposal ID: AST 0134373Institution: University of Colorado at BoulderPI: Nickolay GnedinDr. Gnedin is awarded funds at the University of Colorado at Boulder to further develop new methods of modeling the first reionization of the early universe. Current data on the cosmic background radiation indicate that the gas content of the universe remained mostly neutral from the time of recombination at a redshift of about 1000 to a time corresponding to a redshift of about twenty. Observations of quasars at redshifts of about six indicated that, at that time, the intergalactic medium was highly ionized. Thus this "reionization", the shift of intergalactic gas from mostly neutral to mostly ionized, must have happened sometime between the times corresponding to redshifts of six and twenty. Dr. Gnedin will make significant improvements on numerical methods of modeling radiative transfer with the hope of achieving numerical convergence. These models will be able to make quantitatively accurate predictions for the evolution of the intergalactic medium for the first time. Dr. Gnedin will further compare the model results to "Lyman Break Galaxies," some of the most primordial observed galaxies, in an attempt to understand their formation.Dr. Gnedin will integrate his teaching and research by developing a new undergraduate course in cosmology for non-science majors, and developing the cosmology portion of a web-based course in general introductory astronomy. The web-based work will include original simulations drawn from his research. He will also work with undergraduate majors to develop a new planetarium show on cosmology.