QSO Absorption Lines and Cosmology

类星体光谱中观测到的QSO吸收谱线提供了一种研究星系内星际气体和星系间介质中沿类星体视线的气体的方法。萨金特博士正在类星体吸收线研究项目中扩展观察和分析。他正在凯克10米望远镜上使用高分辨率梯队光谱仪（HIRES）。有三个目标：(1)研究星系和星系间介质的重元素含量作为宇宙时间的函数从红移约5（当宇宙约为现在年龄的10%时）到现在的演化；(2)利用引力透镜类星体或类星体对多幅图像的吸收谱线，在10pc ~ 100kpc尺度上研究星系和星系间空间的气体结构；(3)研究电离氢的紫外辐射的超星系通量的宇宙演化。本研究探讨了类星体和星系在不同宇宙时期对电离通量的相对重要性。

QSO absorption lines and comsologyWallace SargentAbsorption lines observed in the spectra of quasars provide a way to study the interstellar gas in galaxies and gas in the intergalactic medium along the line of sight to the quasar. Dr. Sargent is extending observations and analyses in a program of quasar absorption line studies. He is using the High Resolution Echelle Spectrograph (HIRES) on the Keck 10 meter telescopes. There are three objectives: (1) to study the evolution of the heavy element content of galaxies and the intergalactic medium as a function of cosmic time from redshift about 5 (when the universe was about 10% of its present age) forward to the present epoch; (2) to study the structure of the gas in galaxies and intergalactic space on scales ranging from 10pc to 100kpc using the absorption lines observed in multiple images of gravitationally lensed quasars or quasar pairs, and (3) to study the cosmical evolution of the meta-galactic flux of UV radiation capable of ionizing hydrogen. This investigation addresses the relative importance of the contributions of quasars and galaxies to the ionizing flux at different cosmic epochs.