A molecular Einstein ring: imaging a starburst disk surrounding a quasi-stellar object.
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.
Carilli
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CL
National Radio Astronomy Observatory, Post Office Box O, Socorro, NM 87801, USA.
Lewis
G F
GF
Djorgovski
S G
SG
Mahabal
A
A
Cox
P
P
Bertoldi
F
F
Omont
A
A