Star-Forming Galaxies at z~2: An Emerging Picture of Galaxy Dynamics and Assembly

TL;DR

This study uses integral-field spectroscopy to analyze z~2 star-forming galaxies, revealing many are large, rotating, clumpy disks formed by smooth gas inflow, shedding light on early galaxy evolution.

Contribution

It provides the first detailed kinematic analysis of a significant sample of z~2 star-forming galaxies, demonstrating their disk-like nature and formation via gas inflow rather than mergers.

Findings

Over one-third are large, rotating disks.

Disks are clumpy, thick, and rapidly star-forming.

Disks follow local scaling relations at z~2.

Abstract

In these proceedings, we summarize recent results from our "SINS" VLT/SINFONI integral-field survey, focusing on the 52 detected UV/optically-selected star-forming galaxies at z~2. Our H-alpha emission-line imaging and kinematic data of these systems illustrates that a substantial fraction (> 1/3) of these galaxies are large, rotating disks and that these disks are clumpy, thick, and forming stars rapidly. We compare these systems to local disk scaling relations and find that the backbones of these relations are already in place at z~2. Detailed analysis of the large disks in our sample provides strong evidence that this population cannot result from a merger-dominated formation history and instead must be assembled by the smooth but rapid inflow of gas along filaments. These systems will then secularly evolve from clump-dominated disks to bulge-dominated disks on short timescales, a phenomenon that is observed in our SINS observations and is consistent with predictions from numerical simulations. These results provide new and exciting insights into the formation of bulge-dominated galaxies in the local Universe.