title: A molecular Einstein ring: imaging a starburst disk surrounding a quasi-stellar object.
abstract: Images of the molecular CO 2-1 line emission and the radio continuum emission from the redshift 4.12 gravitationally lensed quasi-stellar object (QSO) PSS J2322+1944 reveal an Einstein ring with a diameter of 1.5". These observations are modeled as a star-forming disk surrounding the QSO nucleus with a radius of 2 kiloparsecs. The implied massive star formation rate is 900 solar masses per year. At this rate, a substantial fraction of the stars in a large elliptical galaxy could form on a dynamical time scale of 108 years. The observation of active star formation in the host galaxy of a high-redshift QSO supports the hypothesis of coeval formation of supermassive black holes and stars in spheroidal galaxies.
authors.affiliation: National Radio Astronomy Observatory, Post Office Box O, Socorro, NM 87801, USA.
authors.forename: C L
authors.initials: CL
authors.lastname: Carilli
authors.forename: G F
authors.initials: GF
authors.lastname: Lewis
authors.forename: S G
authors.initials: SG
authors.lastname: Djorgovski
authors.forename: A
authors.initials: A
authors.lastname: Mahabal
authors.forename: P
authors.initials: P
authors.lastname: Cox
authors.forename: F
authors.initials: F
authors.lastname: Bertoldi
authors.forename: A
authors.initials: A
authors.lastname: Omont