APM 08279+5255 optical-to-UV spectrum

The spectroscopic data are taken with the optical DOLoRes and near-IR NICS instruments at TNG, and include the previously unexplored range between CIII] {lambda}1910 and [OIII] {lambda}{lambda}4959,5007. We investigate the possible presence of multiple BALs by computing "balnicity" and absorption indexes (i.e. BI, BI_0_ and AI) for the transitions SiIV {lambda}1400, CIV {lambda}1549, AlIII {lambda}1860 and MgII {lambda}2800.

No clear evidence for the presence of absorption features is found in addition to the already known, prominent BAL associated to C IV, which supports a high-ionization BAL classification for APM 08279+5255. We also study the properties of the [OIII], H{beta} and MgII emission lines. We find that [OIII] is intrinsically weak (F_[OIII]_/F_H{beta}_<~0.04), as it is typically found in luminous quasars with a strongly blueshifted CIV emission line (2500km/s for APM 08279+5255).