DISCOVERY OF AN APPARENT COMPANION GALAXY TO Q1548+0917 WITH Z = 2.7581

We report the discovery of a resolved "companion" to the QSO Q1548 + 0917 (Z(em) = 2.749). The object is unique in that it was discovered on the basis of broadband images, and subsequent spectroscopy has revealed that the companion has a redshift approximately 1000 km s-1 greater than that of the QSO, that it has an essentially flat ultraviolet continuum, and that the Lyman alpha equivalent width is at least an order of magnitude smaller than for "typical" high redshift radio galaxies (although the UV luminosity is comparable). The companion, which we designate C1548 + 0917, is located 4.8" from the QSO [a projected distance of approximately 30h-1 kpc (q0 = 0)], and is at least approximately 40h-1 kpc in size. It is apparently of low ionization state, based on the absence of detected high ionization lines. We discuss the possible nature of C1548 + 0917, and we present new spectroscopic observations of the "prototypical" case of a Lyman alpha emitting companion to a high redshift QSO, PKS 1614 + 0508 A, as a comparison. VLA observations of Q1548 + 0917 show that the QSO is a very weak (0.6 mJy at 8.4 Ghz) radio source, with no significant resolved structure; thus, C1548 + 0917 appears to be the first case of a "radio-quiet" continuum object (probably a galaxy) discovered in the viscinity of what must also be considered to be a "radio-quiet" QSO at high redshift. In addition to the discrete companion, we find evidence for extended Lyman alpha emission associated with the QSO itself. We discuss these findings in the light of recent results which find resolved Lyman alpha structure and continuum nebulosity in the vicinity of radio-loud QSOs.