Keck/OSIRIS IFU Detection of a z $\sim$ 3 Damped Lyman Alpha Host Galaxy

TL;DR

This study uses advanced adaptive optics and integral field spectroscopy to detect and analyze the emission properties and kinematics of a galaxy at z~3, providing insights into its mass and star formation activity.

Contribution

First detection of a z~3 DLA host galaxy using Keck/OSIRIS IFU with adaptive optics, revealing its emission lines, star formation rate, and kinematic features.

Findings

Detected [OIII] and Hβ emission lines from the galaxy.

Estimated dynamical mass of approximately 3.1 billion solar masses.

Star formation rate estimated between 7.1 and 13.6 solar masses per year.

Abstract

We present Keck/OSIRIS infrared IFU observations of the $z = $ 3.153 sub-DLA DLA2233+131, previously detected in absorption to a background quasar and studied with single slit spectroscopy and PMAS integral field spectroscopy (IFU). We used the Laser Guide Star Adaptive Optics (LGSAO) and OSIRIS IFU to reduce the point-spread function of the background quasar to FWHM$\sim$0.15 arcseconds and marginally resolve extended, foreground DLA emission. We detect [OIII]$\lambda$5007 emission with a flux F$^{[OIII]\lambda5007}$ = $(2.4\pm0.5)\times10^{-17}$ erg s$^{-1}$ cm$^{-2}$, as well as unresolved [OIII]$\lambda$4959 and H$\beta\lambda$4861 emission. Using a composite spectrum over the emission region, we measure dynamical mass $\sim$ $3.1\times10^9$ M$_{\odot}$. We make several estimates of star formation rate using [OIII]$\lambda$5007 and H$\beta\lambda$4861 emission, and measure a star formation rate of $\sim$ $7.1- 13.6$ M$_{\odot}$ yr$^{-1}$. We map [OIII]$\lambda$5007 and H$\beta\lambda$4861 emission and the corresponding velocity fields to search for signs of kinematic structure. These maps allow for a more detailed kinematic analysis than previously possible for this galaxy. While some regions show slightly red and blue-shifted emission indicative of potential edge-on disk rotation, the data are insufficient to support this interpretation.