Nature 382, 428 - 431 (01 August 1996); doi:10.1038/382428a0

Molecular gas and dust around a radio-quiet quasar at redshift 4.69

Alain Omont^*, Patrick Petitjean^*†, Stéphane Guilloteau^‡, Richard G. McMahon^§, P. M. Solomon & Emmanuel Pécontal^¶

^*Institut d'Astrophysique de Paris-CNRS, 98bis Bd Arago, F-75014 Paris, France
^†DAEC, URA CNRS 173, Observatoire de Paris-Meudon, F-92195 Meudon, France
^‡ Institut de Radio Astronomie Millimetrique, F-38460 St Martin d'Heres, France
^§ Institute of Astronomy, Madingley Road, Cambridge CBS OHA, UK
Astronomy Program, State University of New York, Stony Brook, New York 11794-2100, USA
^¶ Centre de Recherche Astronomique de Lyon, CNRS UMR 142, 9 Avenue Charles Andre, F-69561, St Genis Laval, France

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 large amounts of dust in quasars and radio galaxies at redshifts z > 4 shows 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 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, separated by a few arc seconds, which could indicate either the presence of a companion to the quasar or gravitational lensing of the quasar itself. Regardless of the precise interpretation of the maps, the detection of carbon monoxide confirms the presence of a large mass of molecular gas in one of the most distant galaxies known, and shows that conditions conducive to huge bursts of star formation existed in the very early Universe.

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