Placing High-Redshift Quasars in Perspective: a Catalog of Spectroscopic Properties from the Gemini Near Infrared Spectrograph -- Distant Quasar Survey

TL;DR

This paper presents a large, uniform spectroscopic catalog of high-redshift quasars from the GNIRS-DQS, enabling improved measurements of their properties and insights into their evolution over cosmic time.

Contribution

It provides the largest homogeneous spectroscopic dataset of SDSS quasars at 1.5-3.5 redshift, covering key emission lines for better understanding of quasar properties.

Findings

Enhanced redshift and black hole mass estimation methods.

Insights into spectral property dependence on redshift and luminosity.

Foundation for future studies on quasar evolution.

Abstract

We present spectroscopic measurements for 226 sources from the Gemini Near Infrared Spectrograph - Distant Quasar Survey (GNIRS-DQS). Being the largest uniform, homogeneous survey of its kind, it represents a flux-limited sample ($m_{i}$ ${\lesssim}$ 19.0 mag, $H$ ${\lesssim}$ 16.5 mag) of Sloan Digital Sky Survey (SDSS) quasars at 1.5 ${\lesssim}$ $z$ ${\lesssim}$ 3.5 with a monochromatic luminosity (${\lambda}L_{\lambda}$) at 5100 ${\unicode{xC5}}$ in the range of $10^{44} - 10^{46}$ erg $\rm{s}^{-1}$. A combination of the GNIRS and SDSS spectra covers principal quasar diagnostic features, chiefly the C IV ${\lambda}$1549, Mg II ${\lambda}{\lambda}$2798, 2803, H${\beta}$ ${\lambda}$4861, and [O III] ${\lambda}{\lambda}$4959, 5007 emission lines, in each source. The spectral inventory will be utilized primarily to develop prescriptions for obtaining more accurate and precise redshifts, black hole masses, and accretion rates for all quasars. Additionally, the measurements will facilitate an understanding of the dependence of rest-frame ultraviolet-optical spectral properties of quasars on redshift, luminosity, and Eddington ratio, and test whether the physical properties of the quasar central engine evolve over cosmic time.