The Gravitational Lens B1608+656. I.V‐,I‐, andH‐BandHubble Space TelescopeImaging

We present a multi-wavelength analysis of high-resolution observations of thequadruple lens B1608+656 from the HST archive, acquired with WFPC2 throughfilters F606W (V-band) and F814W (I-band), and with NIC1 in filter F160W(H-band). In the three bands, the observations show extended emission from the fourimages of the source in a ring-like configuration that surrounds the two,resolved, lensing galaxies. B1608+656 was discovered as a double-lobed radiosource, and later identified as a post-starburst galaxy in the optical. Basedon photometry and optical spectroscopy we estimate that the stellar populationof the source has an age of $\sim$ 500 Myr. This provides a model for thespectrum of the source that extends over spectral regions where no observationsare available, and is used to generate Tiny Tim PSFs for the filters.Deconvolutions performed with the Lucy-Richardson method are presented, and thelimitations of these restorations is discussed. V$-$I and I$-$H color maps showevidence of extinction by dust associated with one of the lensing galaxies, alate type galaxy presumably disrupted after its close encounter with the otherlens, an elliptical galaxy. The extinction affects the two lens galaxies andtwo of the four multiple images. The diagnostic of wavelength-dependent effectsin the images shows that corrections for contamination with light from thelenses, extinction, and PSF convolution need to be applied before using theextended structure in the images as a constraint on lens models. We willpresent the restoration of the images in a subsequent paper.Comment: 29 pages. Submitted to Ap