The Team Keck Redshift Survey 2: MOSFIRE Spectroscopy of the GOODS-North Field

TL;DR

The TKRS2 survey uses MOSFIRE spectroscopy to study galaxy emission lines at high redshift, revealing insights into galaxy composition and ionization, and providing publicly available spectral data for further research.

Contribution

This work presents the first detailed sensitivity analysis of MOSFIRE across wavelengths and releases a comprehensive dataset of high-redshift galaxy spectra.

Findings

Detection of strong emission lines in z~2 galaxies

Evidence for higher N/O ratios or low-metallicity AGN activity

Public release of spectral data for community use

Abstract

We present the Team Keck Redshift Survey 2 (TKRS2), a near-infrared spectral observing program targeting selected galaxies within the CANDELS subsection of the GOODS-North Field. The TKRS2 program exploits the unique capabilities of MOSFIRE, an infrared multi-object spectrometer which entered service on the Keck I telescope in 2012 and contributes substantially to the study of galaxy spectral features at redshifts inaccessible to optical spectrographs. The TKRS2 project targets 97 galaxies drawn from samples that include z~2 emission-line galaxies with features observable in the JHK bands as well as lower-redshift targets with features in the Y band. We present a detailed measurement of MOSFIRE's sensitivity as a function of wavelength, including the effects of telluric features across the YJHK filters. The largest utility of our survey is in providing rest-frame-optical emission lines for z>1 galaxies, and we demonstrate that the ratios of strong, optical emission lines of z~2 galaxies suggest the presence of either higher N/O abundances than are found in z~0 galaxies or low-metallicity gas ionized by an active galactic nucleus. We have released all TKRS2 data products into the public domain to allow researchers access to representative raw and reduced MOSFIRE spectra.