Ultraviolet Structure in the Lensed QSO 0957+561

Abstract

Imaging and spectra of the lensed QSO pair 0957+561 are presented and discussed. The data are principally those from the Space Telescope Imaging Spectrograph near-UV MAMA and cover rest wavelengths from 850 to 1350 Å. The QSOs are both extended over about 1", with morphology that matches with a small rotation and includes one feature aligned with the VLBI radio jets. This is the first evidence of lensed structure in the host galaxy. The off-nuclear spectra arise from emission-line gas and a young stellar population. The gas has velocity components with radial velocities at least 1000 km s^-1 with respect to the QSO broad-line region and may be related to the damped Lyα absorber in the nuclear spectra.

Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Unversities for Research in Astronomy, Inc., under NASA contract NAS 5-26555.