New Windows on Damped Lyman Alpha Protogalaxies

这项研究的主要结果将是确定正常星系从现在到红移五年左右的恒星形成历史。这之前是使用最明亮的星系来完成的，但一项新的技术通过观察衰减的莱曼阿尔法系统(DLA)得出了更能代表原星系质量分布的天体的恒星形成率(SFR)，DLA是一组气体中性氢层，在对背景类星体的吸收中被检测到。这种方法将被用来考虑大量的问题，包括SFR如何随红移而变化，它与来自发光星系的红移如何比较，SFR如何取决于质量、中性氢柱密度、速度宽度和金属丰度，它与理论预测如何比较，恒星形成是否仅限于中心凸起或发生在整个吸收气体中，以及DLA是否与发光星系在空间上相关。所有结果将最终进入一个可普遍访问的数据库，该数据库已被其他研究人员使用。这些项目涉及不同级别的学生以及初级研究人员，包括来自代表性不足群体的一些人。

AST-0307824WolfeThe primary result from this research will be to determine the star formation history of normal galaxies from the present to redshifts around five. This has previously been done using the most luminous galaxies, but a new technique derives star formation rates (SFRs) for objects more representative of the protogalactic mass distribution, by observing damped Lyman alpha systems (DLAs), a population of gaseous neutral hydrogen layers detected in absorption toward background quasars. This method will be used to consider a large number of issues, including how the SFR varies with redshift, how it compares to that derived from luminous galaxies, how the SFR depends on mass, neutral hydrogen column density, velocity width and metallicity, how it compares to theoretical predictions, whether star formation is confined to the central bulge or occurs throughout the absorbing gas, and whether DLAs are spatially correlated with luminous galaxies.All results will end up in a generally accessible database, already in use by other researchers. The projects involve students at various levels, as well as junior researchers, including some from under-represented groups.***