ZFIRE: The Kinematics of Star-Forming Galaxies as a Function of Environment at z~2

TL;DR

This study analyzes the kinematics of 75 star-forming galaxies at z~2 using NIR spectroscopy, finding that their internal dynamics are similar regardless of whether they are in clusters or the field, and suggesting baryons dominate within their central regions.

Contribution

First detailed kinematic analysis of z~2 star-forming galaxies in different environments using Keck/MOSFIRE data, comparing cluster and field galaxy properties.

Findings

H$eta$ emission-line velocity dispersions range from 50-230 km/s.

No significant kinematic differences between cluster and field galaxies.

Baryons dominate within the central effective radius of these galaxies.

Abstract

We perform a kinematic analysis of galaxies at $z\sim2$ in the COSMOS legacy field using near-infrared (NIR) spectroscopy from Keck/MOSFIRE as part of the ZFIRE survey. Our sample consists of 75 Ks-band selected star-forming galaxies from the ZFOURGE survey with stellar masses ranging from log(M$_{\star}$/M$_{\odot}$)$=9.0-11.0$, 28 of which are members of a known overdensity at $z=2.095$. We measure H$\alpha$ emission-line integrated velocity dispersions ($\sigma_{\rm int}$) from 50$-$230 km s$^{-1}$, consistent with other emission-line studies of $z\sim2$ field galaxies. From these data we estimate virial, stellar, and gas masses and derive correlations between these properties for cluster and field galaxies at $z\sim2$. We find evidence that baryons dominate within the central effective radius. However, we find no statistically significant differences between the cluster and the field, and conclude that the kinematics of star-forming galaxies at $z\sim2$ are not significantly different between the cluster and field environments.