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|Title:||X-shooter reveals powerful outflows in z ̃ 1.5 X-ray selected obscured quasi-stellar objects||Authors:||Brusa, M.
La Franca, F.
|Issue Date:||2015||Journal:||MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY||Number:||446||Issue:||3||First Page:||2394||Abstract:||We present X-shooter at Very Large Telescope observations of a sample of 10 luminous, X-ray obscured quasi-stellar objects (QSOs) at z ̃ 1.5 from the XMM-COSMOS survey, expected to be caught in the transitioning phase from starburst to active galactic nucleus (AGN)-dominated systems. The main selection criterion is X-ray detection at bright fluxes (L<SUB>X</SUB> ≳ 10<SUP>44</SUP> erg s<SUP>-1</SUP>) coupled to red optical-to-near-infrared-to-mid-infrared colours. Thanks to its large wavelength coverage, X-shooter allowed us to determine accurate redshifts from the presence of multiple emission lines for five out of six targets for which we had only a photometric redshift estimate, with an 80 per cent success rate, significantly larger than what is observed in similar programs of spectroscopic follow-up of red QSOs. We report the detection of broad and shifted components in the [O III] λλ5007, 4959 complexes for six out of eight sources with these lines observable in regions free from strong atmospheric absorptions. The full width at half-maximum (FWHM) associated with the broad components are in the range FWHM ̃ 900-1600 km s<SUP>-1</SUP>, larger than the average value observed in Sloan Digital Sky Survey type 2 AGN samples at similar observed [O III] luminosity, but comparable to those observed for QSO/ultraluminous infrared galaxies systems for which the presence of kpc scale outflows has been revealed through integral field unit spectroscopy. Although the total outflow energetics (inferred under reasonable assumptions) may be consistent with winds accelerated by stellar processes, we favour an AGN origin for the outflows given the high outflow velocities observed (v > 1000 km s<SUP>-1</SUP>) and the presence of strong winds also in objects undetected in the far-infrared.||Acknowledgments:||This work is based on observations made at the European Southern Observatory, Paranal, Chile (ESO program 090.A-0830(A)) and on observations obtained with XMM–Newton and Herschel , two ESA Science Missions with instruments and contributions directly funded by ESA Member States and the USA (NASA). MB and AB are grateful to A. Mehner and R . Wesson for the support at the telescope. MB, AB and GC acknowledge useful discussion with N. Neumeyer, A. Modigliani, M. Romaniello and the ESO USD team, for reflex support, and are grateful to A. Mucciarelli and S. Piranomonte for help on X-shooter data reduction and flux calibration. MB gratefully thank J. Mullaney, D. Kashino and T. Urrutia for providing us their data sets, and Chiara Feruglio, Francesca Civano, Mark Sargent and Kirpal Nandra for useful discussions. MB and MP acknowledge support from the FP7 Career Integration Grant ‘eEASy’ (‘SMBH evolution through cosmic time: from current surveys to eROSITA– Euclid AGN Synergies’, CIG 321913). AB work is supported by the INAF-Fellowship Program. Support for this publication was provided by the Italian National Institute for Astrophysics (INAF) through PRIN-INAF 2011 (‘Black hole growth and AGN feedback through the cosmic time’) and PRIN-INAF-2012 (‘The life cycle of early black holes’), and by the Italian Ministry for School, University and Research (MIUR) through PRIN-MIUR 2010-2011 (‘The dark Universe and the cosmic evolution of baryons: from current surveys to Euclid ’). We gratefully acknowledge the unique contribution of the entire COSMOS collaboration for making their excellent data products publicly available; more information on the COSMOS survey is available at http://www.astro.caltech.edu/∼cosmos .||URI:||http://hdl.handle.net/20.500.12386/23690||URL:||https://academic.oup.com/mnras/article/446/3/2394/2891853||ISSN:||0035-8711||DOI:||10.1093/mnras/stu2117||Bibcode ADS:||2015MNRAS.446.2394B||Fulltext:||open|
|Appears in Collections:||1.01 Articoli in rivista|
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checked on Sep 24, 2020
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