Vlt + Uves Spectroscopy of the Ca Ii Lobal Quasar Sdss

We study high-resolution spectra of the ‘overlapping-trough’ low-ionization broad absorption line (LoBAL) quasar SDSS 0300+0048. The Ca II, Mg II and Mg I column densities in SDSS 0300+0048 are the largest reported to date for any BAL outflow. The broad Ca II absorption in this object is mildly blended, but the blending can be disentangled to measure the Ca II column density, which is large enough that the outflow must include a strong hydrogen ionization front. The outflow begins at a blueshift of ∼1650km s from the systemic redshift. The lowest velocity BAL region produces strong Ca II absorption but does not produce significant excited Fe II absorption, while the higher velocity excited Fe II absorption region produces very little Ca II absorption. This segregation can only really be explained by a disk wind outflow. Whether the outflow is smooth or clumpy, we conclude that the Ca II BAL region has a density high enough to populate excited levels of Fe II, but a temperature low enough to prevent them from being significantly populated. This requirement means the Ca II BAL region has T . 1100 K, and perhaps even T . 550 K. This object also has an associated absorption line system (AAL) which exhibits partial covering, and therefore is likely located near the central engine. Whether or not it is associated with the BAL outflow is unclear. Blending of the AAL with the BAL trough shows that the spatial region covered by the BAL outflow can vary over velocity differences of ∼1700 kms. Subject headings: quasars: absorption lines, quasars: general, quasars: emission lines