Quasar Properties from the Sloan Digital Sky Survey. III. The Quasars Obtained by the SDSS-IV

Abstract

This paper provides the compilations of properties of the quasars newly obtained by the Sloan Digital Sky Survey (SDSS) during the fourth stage (SDSS-IV). The catalog is available on the journal's website. We have measured the main properties of emission lines around C iv , Mg ii , H β , and H α spectral regions. We estimate the quasar redshifts from our fits of narrow [O iii ], broad Mg ii , and broad C iv emission lines and find that the best redshifts included in DR16Q are robust with respect to our measurements. Based on the broad C iv , Mg ii , H β , and/or H α emission lines, we calculate the virial black hole mass with empirical relationships provided by previous works. Systematic biases are found among the different line-based mass estimators.

Keywords

• Astronomy data reduction
• Active galaxies
• Quasars
• Supermassive black holes
• Catalogs