摘要：We have performed a high sensitivity observation of the UFO/BAL quasar APM 08279+5255 at z = 3.912 with NOEMA at 3.2 mm, aimed at detecting fast moving molecular gas. We report the detection of blueshifted CO(4−3) with maximum velocity (v95%) of −1340 km s-1, with respect to the systemic peak emission, and a luminosity of L′ = 9.9 × 109μ-1 K km s-1 pc-2, where μ is the lensing magnification factor. We discuss various scenarios for the nature of this emission and conclude that this is the first detection of fast molecular gas at redshift > 3. We derived a mass flow rate of molecular gas in the range Ṁ = 3−7.4 × 103M⊙/yr and momentum boost ṖOF/ṖAGN ~ 2−6, which is therefore consistent with a momentum conserving flow. For the largest ṖOF the scaling is also consistent with an energy conserving flow with an efficiency of ~10−20%. The present data can hardly discriminate between the two expansion modes. The mass loading factor of the molecular outflow η = ṀOF/SFR is ≫ 1. We also detected a molecular emission line at a frequency of 94.83 GHz corresponding to a rest-frame frequency of 465.8 GHz; we tentatively identified this frequency with the cation molecule N2H+(5−4), which would be the first detection of this species at high redshift. We discuss the alternative possibility that this emission is due to a CO emission line from the, so far undetected, lens galaxy. Further observations of additional transitions of the same species with NOEMA can discriminate between the two scenarios.
