MOLECULAR GAS AND DUST AROUND A RADIO-QUIET QUASAR AT REDSHIFT-4.69

GALAXIES are believed to have formed a large proportion of their stars in giant bursts of star formation early in their lives, but when and how this took place are still very uncertain. The presence(1-6) of lar ge amounts of dust in quasars and radio galaxies at redshifts z > 4 sh ows that some synthesis of heavy elements had already occurred at this time. This implies that molecular gas-the building material of stars- should also be present, as it is in galaxies at lower redshifts (z app roximate to 2.5, refs 7-10). Here we report the detection of emission from dust and carbon monoxide in the radio-quiet quasar BR1202 - 0725, at redshift z = 4.69. Maps of these emissions reveal two objects, sep arated by a few are seconds, which could indicate either the presence of a companion to the quasar of gravitational lensing of the quasar it self. Regardless of the precise interpretation of the maps, the detect ion of carbon monoxide confirms the presence of a large mass of molecu lar gas in one of the most distant galaxies known, and shows that cond itions conducive to huge bursts of star formation existed in the very early Universe.