Star Formation in SpARCS J0330: Bridging the Gap Between Protoclusters and Clusters

At z > 2, many studies have identified protoclusters - overdensities of galaxies spanning tens of Mpc in size and hosting some of the most vigorous star formation observed in the Universe to date. Conversely, galaxy clusters are typically observed at z < 1 and are massive, virialised and abundant in quiescent, elliptical galaxies. Current models of galaxy formation and evolution predict that protoclusters will evolve into z ~ 0 massive galaxy clusters, and so there must be some rapid, environmentally-driven quenching of star formation at z ~ 1 that transforms protoclusters into clusters. In order to understand this evolution, we must search for overdensities of galaxies at the onset of cluster formation at which time we can observe the full web of activity: the assembly of a collapsed cluster core feeding on the star-forming filamentary material that resides in the protocluster web. In this project, we present an analysis of SpARCS J0330, one of the most massive, high-z galaxy clusters discovered to date. By building up SEDs with up to 20-band photometry for the spectroscopically confirmed cluster members, as well as for the potential cluster members, we aim to map out distant, star-forming galaxies over a ~15Mpc region across the cluster, bridging the gap between studies of high-z protoclusters and local galaxy clusters, and providing critical insights into how galaxy clusters form out of the cosmic web.