Galaxy Clusters at z > 1

该奖项由2009年美国复苏和再投资法案(公法111-5)资助。威尔逊博士将研究红移为0.87z1.34的10个星系团，这些星系团被认为是宇宙扩张到现在大小的一半时的样子。这些星系团是从一项调查中挑选出来的，该调查将斯皮策太空望远镜50平方度的3.6微米图像与地面900纳米处的图像结合在一起，以挑选出古老的椭圆星系的红色序列。这些星系团是一些距离最远的星系团，它们的距离已经从光谱上得到了确认。威尔逊博士和她的团队将为每个星系团中的大约50个星系寻找额外的光谱，校准星系团质量和丰富度之间的关系，以便与早期星系形成的宇宙学模拟进行比较。额外的光学图像将在光学和近红外波段提供总共10个色带，用于估计恒星形成的速度(包括尘埃遮挡和其他情况)和每个星系中存在的恒星质量。PI还在1.5z2之间的“红移沙漠”中寻找更远的候选星团的近红外光谱；这些星团将是在这个红移范围内的第一个被证实的星团。这种星系团的样本对于与模型的比较特别有价值，因为它是以可量化的方式选择的，但与X射线选择的星系团的样本不同。研究生将通过参与研究来进行培训。威尔逊博士将把这项研究的结果整合到她的本科教学中，并将继续她在教师教育和公共推广计划方面的工作。数据产品将在网络上分发。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).Dr Wilson will study ten clusters of galaxies at redshift 0.87 z 1.34, which are seen as they were when the cosmos had expanded to only about half its present size. The clusters are chosen from a survey that combined 3.6-micron images from a 50-square degree survey with the Spitzer Space telescope with images from the ground at 900nm, to pick out the red sequence of old elliptical galaxies. These are some of the most distant galaxy clusters for which distances have been confirmed spectroscopically. Dr Wilson and her team will seek additional spectroscopy for about 50 galaxies in each cluster, calibrating the relation between cluster mass and richness for comparison with cosmological simulations of early galaxy formation. Additional optical images will provide a total of 10 color-bands in the optical and near-infrared, which will be used to estimate the rate of star formation (both dust-obscured and otherwise) and the stellar masses present in each galaxy. The PI also seeks near-infrared spectroscopy for more distant candidate clusters in the 'redshift desert' between 1.5 z 2; these would be the first confirmed clusters in this redshift range. This sample of clusters is especially valuable for comparison with models, because it is selected in a quantifiable way, but one that is different from that for X-ray-selected clusters.A graduate student will be trained by participating in the research. Dr Wilson will integrate results of this research into her undergraduate teaching, and will continue her work in teacher-education and public-outreach programs. Data products will be distributed on the web.