Using a sample of 1000 quasars from SDSS Data Release ten quasar catalog of redshifts 0< z ≤ 6, we study the physical properties of quasars at this redshift range. We have studied the number density of quasars, colors changes at low and high redshifts, the scattering in the color as a function of the redshift of quasars, and calculated the median of the colors. Our results investigated that the majority of quasars were found at low redshifts due to the massive black holes. We also conclude that quasars at low redshifts are outliers from the ugri stellar locus, and the high redshift quasars are outliers from griz stellar locus.
Keywords: : Quasars - Catalog: General, Methods: Statistical, Redshift
