On the discovery of fast molecular gas in the UFO/BAL quasar APM 08279+5255 at z = 3.912

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Feruglio, C 
Ferrara, A 
Bischetti, M 
Downes, D 
Neri, R 

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′=9.9×109 μ−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 derive a mass flow rate of molecular gas in the range M˙=3−7.4×103 M/yr, and momentum boost P˙OF/P˙AGN∼2−6, therefore consistent with a momentum conserving flow. For the largest P˙OF the scaling is also consistent with a energy conserving flow with an efficiency of $\sim$10-20%. The present data can hardly discriminate between the two expansion modes. The mass loading factor of the molecular outflow η=M˙OF/SFR is >>1. We also detect a molecular emission line at a frequency of 94.83 GHz, corresponding to a rest frame frequency of 465.8 GHz, which we tentatively identified 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.

galaxies: active, quasars: emission lines, submillimeter: ISM, X-rays: individuals: APM 08279+5255, quasars: individual: APM 08279+5255, quasars: general
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Astronomy and Astrophysics
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EDP Sciences
European Research Council (695671)
Science and Technology Facilities Council (ST/M001172/1)