1999AJ....117..671N

We present imaging polarimetry of the extremely luminous, redshift 2.3 IRAS source FSC 10214+4724. The observations were obtained with HST's Faint Object Camera in the F437M filter, which is free of strong emission lines. The 0".7 long arc is unresolved to 0".04 FWHM in the transverse direction and has an integrated polarization of 28%±3%, in good agreement with ground-based observations. The polarization position angle varies along the arc by up to 35°. The overall position angle is 62°±3° east of north. No counterimage is detected to B=27.5 mag (3 σ), giving an observed arc to counterimage flux ratio greater than 250, considerably greater than the flux ratio of 100 measured previously in the I band. This implies that the configuration of the object in the source plane at the B band is different from that at I band and/or that the lensing galaxy is dusty.