Strongly gravitationally lensed quasars and the distribution of dark matter in galaxies

这个项目使用强透镜类星体(由于中间星系的光弯曲而呈现多幅图像的类星体)来研究星系中暗物质作为半径的函数的部分贡献，以及暗物质分布的平坦和笨拙。暗物质和常规物质，主要是恒星，在视线上做出了类似的贡献。类星体的发射区域大多足够小，以至于单个恒星充当透镜，导致每幅图像的亮度波动。对这些波动的观测将被用来测量正常物质和暗物质成分的相对贡献，从而测量其比例。尽管简单的模型准确地再现了多幅图像的位置，但它们不能正确地预测通量比率，可能是由于小尺度结构的原因。仔细监测这些来自不同类星体发射区的通量比异常将被用来确定有多少是由于暗物质亚结构，有多少是由于恒星的微透镜。对螺旋星系产生的多个类星体图像的罕见情况进行光谱观测，将有助于测量可见盘和暗晕对引力势形状的相对贡献。这些观测将使用麦哲伦望远镜进行。目前的首席调查员继续努力改善图像质量，这不仅有助于这项研究，而且对所有五个伙伴机构的天文学家都有价值。本科生将继续参与这位研究员的所有研究。

AST-0607601SchechterThis project uses strongly lensed quasars (those which present multiple images due to light bending by an intervening galaxy) to study the fractional contribution of dark matter in galaxies as a function of radius, and the flattening and clumpiness of the dark matter distribution. Dark matter and conventional matter, mostly stars, make comparable contributions along the line of sight. The emitting regions of quasars are mostly small enough that individual stars act as lenses, causing fluctuations in the brightness of each image. Observations of these fluctuations will be used to measure the relative contributions, and thus the proportions, of the normal and dark matter components.Although simple models accurately reproduce the locations of multiple images, they do not correctly predict the flux ratios, presumably due to small-scale structure. Careful monitoring of these flux ratio anomalies from various quasar emission regions will be used to resolve how much is due to dark matter substructure and how much is due to micro-lensing by stars. Spectroscopic observations of the rare cases of multiple quasar images produced by spiral galaxies will be invaluable in helping to measure the relative contributions of the visible disk and dark halo to the shape of the gravitational potential.These observations will be made with the Magellan telescopes. The present principal investigator continues to work to improve image quality, which not only helps with this study but also is of value to the astronomers at all five partner institutions. Undergraduates will continue to be involved in all of this investigator's research.