Galaxies of the z ∼ 2 Universe. I. Grism-selected Rest-frame Optical Emission-line Galaxies

Abstract

Euclid , the Wide Field Infrared Survey Telescope , and the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX) will make emission-line selected galaxies the largest observed constituent in the z  > 1 universe. However, we only have a limited understanding of the physical properties of galaxies selected via their Ly α or rest-frame optical emission lines. To address this problem, we present the basic properties of ∼2000 All-Wavelength Extended Groth Strip International Survey, Cosmological Evolution Survey, Great Observatories Origins Deep Survey-North, Great Observatories Origins Deep Survey-South, and Ultra Deep Survey galaxies identified in the redshift range 1.90 <  z  < 2.35 via their [O ii ], H β , and [O iii ] emission lines in the 3D- Hubble Space Telescope survey. For these z  ∼ 2 galaxies, [O iii ] is generally much brighter than [O ii ] and H β , with typical rest-frame equivalent widths of several hundred Angstroms. Moreover, these strong emission-line systems span an extremely wide range of stellar mass (∼3 dex), star formation rate (∼2 dex), and [O iii ] luminosity (∼2 dex). Comparing the distributions of these properties to those of continuum-selected galaxies, we find that emission-line galaxies have systematically lower stellar masses and lower optical/UV dust attenuations. These measurements lay the groundwork for an extensive comparison between these rest-frame optical emission-line galaxies and Ly α emitters identified in the HETDEX survey.