Redshifts and observed colors of QSOs and active galaxies

While the relationships between observed colors and redshifts for QSOs have been studied, apparently no such study has been conducted for active galaxies (AGs). The present investigation is concerned with the redshift-color and color-color relationships of QSOs and AGs, individually and combined. The investigation has the objective to find out about the type of relationship in each case, the effect of the emission lines on the redshift-color variation, the possibility of a prediction of redshifts from photometric observations, and any evolutionary link between the two classes of objects. The analysis demonstrates that one of the most important properties of the two classes of objects, the color indices, show continuity across the entire observable redshift scale. They are, therefore, possibly the same objects evolutionary linked.