Assembling a High-Redshift Galactic Protocluster: An Imaging Study of MRC1138-262

Abstract

In this thesis we present multiband optical and near infrared imaging observations using FourStar and DECam of an extended field around MRC1138-262, the central galaxy in a forming galactic cluster at a redshift of 2.16. The central part of this field contains a spectroscopically confirmed overdensity of galaxies. We use multiband photometry to identify two new potential cluster members and 16 new field members at redshift near 2.16. Using these galaxies and previously spectroscopically analyzed galaxies, we begin to compare the properties of the cluster galaxies to those in the field. We confirm a significant overdensity of galaxies in the core of the cluster and an overdensity of Ly-alpha emitters. We do not find a significant change in the distribution of red galaxies in the cluster, suggesting a weaker link than previously thought between cluster galaxies and H-alpha emissions.