Red and blue quasars (annotated)

Red and blue quasars
Artist’s impression of red and blue quasars. Red quasar (left): A brief transitional phase where the nascent quasar is enshrouded in gas and dust. This phase appears to be associated with young jets and strong winds, which ultimately drive away the obscuring gas and dust. Blue quasar (right): An unobscured quasar with signatures of evolved jets and less extreme winds.
S. Munro