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Paper: A Large Population of High Redshift Galaxy Clusters in the IRAC Shallow Cluster Survey
Volume: 399, Panoramic Views of Galaxy Formation and Evolution
Page: 322
Authors: Brodwin, M.; Eisenhardt, P.R.; Gonzalez, A.H.; Stanford, S.A.; Stern, D.; Moustakas, L.A.; Brown, M.J.I.; Chary, R.-R.; Galametz, A.
Abstract: We have identified 335 galaxy cluster and group candidates spanning 0 < z < 2, using a 4.5μm selected sample of galaxies in a 7.25 deg2 region in the Spitzer/IRAC Shallow Survey. Using full redshift probability distributions for all galaxies, clusters were identified as 3-dimensional overdensities using a wavelet algorithm. To date 12 clusters at z > 1, and over 60 at z < 0.5 have been spectroscopically confirmed. The mean I-[3.6] color for cluster galaxies up to z ∼ 1 is well matched by a zf = 3 passively evolving model. At z > 1, a wider range of formation histories is needed, but higher formation redshifts (i.e. zf ≥ 4 − 5) are favored for most clusters. The cluster autocorrelation function, measured for the first time out to z = 1.5, is found not to have evolved over the last 10 Gyr, in agreement with the prediction from ΛCDM. The average mass of the IRAC Shallow Cluster Survey sample, inferred from its clustering, is ∼ 1014M.
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