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.
