Detection of molecular gas in the quasar BR1202 - 0725 at redshift z = 4.69

Although great efforts have been made to locate molecular gas-the material out of which stars form-in the early Universe, there have been only two firm detections at high redshift. Both are gravitationally lensed objects at redshift z ≃ 25 (refs 9-14). Here we report the detection of CO emission from the radio-quiet quasar BR1202-0725, which is at redshift z = 469. From the observed CO luminosity, we estimate that almost 10¹¹ solar masses of molecular hydrogen are associated with the quasar; this is comparable to the stellar mass of a present-day luminous galaxy. Our results suggest that BR1202-0725 is a massive galaxy, in which the gas is largely concentrated in the central region, and that it is currently undergoing a large burst of star formation.