A gravitational lens solution for IRAS F10214+4724

We show that the high redshift IRAS source F10214 is highly magnified by the gravitational field of an intervening elliptical galaxy, accounting for its many anomalous properties. Detailed radio and near-IR images identify the IRAS source with a symmetric arc, centered on a red object, or lensing galaxy. To explain the observed structures, the center of the source must much more highly magnified than its outer regions. Lensing predicts a small counterimage to the arc, which we find adjacent to the lensing galaxy. A red component in the observed spectrum suggests a lens redshift of unity, and the lens model yields a mass estimate of M(r<3kpc)\approx10^{11}{M_solar}, consistent with an ordinary elliptical galaxy. We present new high-resolution optical images which show a thin arc of emission, implying an intrinsically small source (