IMAGING OF THE GRAVITATIONAL LENS SYSTEM PG 1115-SPACE-TELESCOPE(080 WITH THE HUBBLE)

This paper is the first of a series presenting observations of gravita tional lenses and lens candidates, taken with the Wide Field/Planetary Camera (WFPC) of the Hubble Space Telescope (HST). We have resolved t he gravitational lens system PG 1115 + 080 into four point sources and a red, extended object that is presumably the lens galaxy; we present accurate relative intensities, colors, and positions of the four imag es, and lower accuracy intensity and position of the lens galaxy, all at the epoch 1991.2. Comparison with earlier data shows no compelling evidence for relative intensity variations between the QSO components having so far been observed. The new data agree with earlier conclusio ns that the system is rather simple, and can be produced by the single observed galaxy. The absence of asymmetry in the HST images implies t hat the emitting region of the quasar itself has an angular radius sma ller than about 10 milliarcsec (100 pc for H-0=50, q0=0.5).