RSAA Colloquia / Seminars / Feast-of-Facts: Friday, 08 June 2018, 14:00-14:20; Duffield Lecture Theatre

Leo Alcorn

"The Proto-cluster Environment at z~2: Kinematics, Metallicity, and Merging Groups"

As near-infrared instrumentation comes into widespread use in extragalactic astronomy, we can observe the rest-frame properties of galaxies in over-dense or proto-cluster environments. These observations provide valuable information on the early affects of environmental density on galaxy evolution, and provide constraints on advanced cosmological simulations such as FIRE and Illustris-TNG. The ZFIRE survey has spectroscopically confirmed two such proto-clusters, at z=2.095 in COSMOS, and at z=1.65 in UDS, using the MOSFIRE instrument on Keck 1. In the COSMOS cluster, we measure gas kinematics from the Hydrogen alpha emission line, and find no cluster-wide effects on kinematics, and a minor correlation between irregular morphology and angular momentum. In addition, we measure gas-phase metallicity on the group scale, attempting to measure indications of gas accretion or metal enrichment in the merging groups that define this proto-cluster. We determine if and when environmental density plays a role in early galaxy properties, which evolutionary processes are affected, and at what scale these processes act on members of over-dense regions at z~2.