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

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 $\text{unicode}xC5$ in the range of ${10}^{44}-{10}^{46}$ erg ${\mathrm{s}}^{-1}$. 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.