The unusual near-infrared morphology of the radio-loud quasar 4C + 09.17

Near-infrared images of the luminous, high-redshift (z= 2.1108), radio-loud quasar 4C + 09.17 reveal a complex structure. The quasar (K= 15.76 mag) is surrounded by three ‘companion’ objects having 17.9 1.5. If this object is at the redshift of 4C + 09.17, it has a luminosity of about 7L^⋆. The faintest companion has colours which are unlike those expected from either a spiral or an E/S0 galaxy at any redshift associated with the 4C +09.17 system. Since this object lies along the same direction as the radio jet/lobe of 4C + 09.17, as well as the extended Lyα emission mapped by Heckman et al., we suggest that this component can be explained as a combination of strong line emission and scattered QSO light. The resolved, diffuse emission surrounding 4C + 09.17 is bright, K~ 17.0 mag, and about 1 mag redder inJ—K than the quasar. If this emission is starlight, a very luminous elliptical host galaxy is implied for 4C +09.17. Scattered and reddened AGN light, emission-line gas, and flux from absorbing galaxies along the line of sight may all contribute to this emission