2005A&A...443..903Z

In this paper we present near infrared (NIR) imaging data of the host galaxy of the broad absorption line quasar (BALQ) at z=2.169, serendipitously found close to 3C 48 (Canalizo et al., 1998AJ....115..890C). The data were obtained with the ESO-VLT camera ISAAC during period 67. We find extended, rest-frame optical emission around the BALQ after subtracting a scaled stellar point spread function from the quasar nucleus in J, H, and Ks. The extended rest-frame optical emission can be interpreted as an approximately 2Gyr old stellar population composing the host galaxy of the BALQ or a stellar population of similar age associated with an intermediate (z=1.667) absorption system spectroscopically identified by Canalizo et al. (1998). The rest-frame-UV emission on the other hand is dominated by a young, ∼500Myr old stellar population (Canalizo et al., 1998AJ....115..890C). The UV/optical colors resemble a mixture of the two populations, of which the young one accounts for about 80%. Assuming that the residual emission is located at the BALQ redshift, we find that the host galaxy has a resolved flux of about 10% of the BALQ flux. The physical scale is quite compact, typical for radio quiet QSOs or Lyman break galaxies at these redshifts, indicating that the systems are still in the process of forming.