New Gravitational Lenses, Time Delays, and Microlensing with the Magellan Telescopes

在这个项目中，将使用两种不同的策略在光学波长上搜索引力透镜类星体。首先，麦哲伦1号（Baade）望远镜将获得6500个已知类星体的常规（但高度自动化的）直接指向图像。其次，利用MPIA 2.2 m望远镜，以0.24弧秒像素和亚弧秒分辨率获得三滤光片1000平方度的直接图像。保守估计，预期的透镜数量为32个，超过了过去二十年来通过光学或无线电技术分别发现的系统数量。由于90%的类星体是无线电静默的，这两次搜索将补充最近成功的无线电搜索，并提供足够明亮的系统，以便在光学波长上进行广泛的后续研究。引力透镜类星体通过质量而不是光来选择星系。透镜星系的样本，通常在中间红移，补充中间红移样本的视星等选择。它们给出的是质量函数而不是光度函数，而光度函数是星系演化模型的一个重要组成部分。透镜类星体也允许测量哈勃常数，这是设定宇宙尺度的宇宙学参数。哈勃常数非常重要，它保证了完全独立于传统视差和标准烛光方法的测量

AST-0206010Schechter, Paul L.In this project two distinct strategies will be used to search at optical wavelengths for gravitationally lensed quasars. First, conventional (but highly automated) pointed direct images will be obtained of 6500 known quasars with the Magellan I (Baade) telescope. Second, direct images in three filters will be obtained for 1000 square degrees with 0.24 arcsecond pixels and subarcsecond resolution with the MPIA 2.2-m telescope. A conservative estimate of the expected number of lenses is 32, exceeding the number of systems found separately in the past two decades by either optical or radio techniques. As 90% of quasars are radio quiet, these two searches will complement recent successful radio searches and furnish systems bright enough for extensive followup at optical wavelengths. Gravitationally lensed quasars select galaxies by mass, rather than light. Samples of lensing galaxies, typically at intermediate redshifts, complement intermediate redshift samples selected by apparent magnitude. They give mass functions rather than luminosity functions, an important component of galaxy evolution models. Lensed quasars also permit measurement of the Hubble constant, the cosmological parameter which sets the scale for the Universe. The Hubble constant is sufficiently important that it warrants a measurement completely independent of the traditional parallax and standard candle based methods.***