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The [O III] emission line luminosity function of optically selected type-2 AGN from zCOSMOS

Bongiorno, A. and Mignoli, M. and Zamorani, G. and Lamareille, F. and Lanzuisi, G. and Miyaji, T. and Bolzonella, M. and Carollo, C. M. and Contini, T. and Kneib, J. P. and Le Fèvre, O. and Lilly, S. J. and Mainieri, V. and Renzini, A. and Scodeggio, M. and Bardelli, S. and Brusa, M. and Caputi, K. and Civano, F. and Coppa, G. and Cucciati, O. and de-la-Torre, S. and de-Ravel, L. and Franzetti, P. and Garilli, B. and Halliday, C. and Hasinger, G. and Koekemoer, A. M. and Iovino, A. and Kampczyk, P. and Knobel, C. and Kovač, K. and Le Borgne, J.-F. and Le-Brun, V. and Maier, C. and Merloni, A. and Nair, P. and Pello, R. and Peng, Y. and Perez-Montero, E. and Ricciardelli, E. and Salvato, M. and Silverman, J. and Tanaka, M. and Tasca, L. and Tresse, L. and Vergani, D. and Zucca, E. and Abbas, U. and Bottini, D. and Cappi, A. and Cassata, P. and Cimatti, A. and Guzzo, L. and Leauthaud, A. and Maccagni, D. and Marinoni, C. and McCracken, H. J. and Memeo, P. and Meneux, B. and Oesch, P. and Porciani, C. and Pozzetti, L. and Scaramella, R. (2010) The [O III] emission line luminosity function of optically selected type-2 AGN from zCOSMOS. Astronomy and Astrophysics, 510 . Art. No. A56. ISSN 0004-6361.

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Aims. We present a catalog of 213 type-2 AGN selected from the zCOSMOS survey. The selected sample covers a wide redshift range (0.15 < z < 0.92) and is deeper than any other previous study, encompassing the luminosity range 10^(5.5) L_☉ < L_([O III]) < 10^(9.1) L_☉. We explore the intrinsic properties of these AGN and the relation to their X-ray emission (derived from the XMM-COSMOS observations). We study their evolution by computing the [O III]λ5007 Å line luminosity function (LF) and we constrain the fraction of obscured AGN as a function of luminosity and redshift. Methods. The sample was selected on the basis of the optical emission line ratios, after applying a cut to the signal-to-noise ratio (S/N) of the relevant lines.We used the standard diagnostic diagrams ([O III]/Hβ versus [N II]/Hα and [O III]/Hβ versus [S II]/Hα) to isolate AGN in the redshift range 0.15 < z < 0.45 and the diagnostic diagram [O III]/Hβ versus [O II]/Hβ to extend the selection to higher redshift (0.5 < z < 0.92). Results. Combining our sample with one drawn from SDSS, we found that the best description of the evolution of type-2 AGN is a luminosity-dependent density evolution model. Moreover, using the type-1 AGN LF we were able to constrain the fraction of type-2 AGN to the total (type-1 + type-2) AGN population. We found that the type-2 fraction decreases with luminosity, in agreement with the most recent results, and shows signs of a slight increase with redshift. However, the trend with luminosity is visible only after combining the SDSS+zCOSMOS samples. From the COSMOS data points alone, the type-2 fraction seems to be quite constant with luminosity.

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Additional Information:© ESO 2010. Received 2 September 2009. Accepted 17 November 2009. A.B. wishes to thank the referee for the useful suggestions that significantly improved the manuscript. A.B. also thank H. Netzer for the the stimulating discussion, R. Fassbender for helping to improve the manuscript and S. Savaglio for sharing the expertise. This work is based on the zCOSMOS ESO Large Program Number 175.A-0839 and was supported by an INAF contract PRIN/2007/, and an ASI grant ASI/COFIS/WP3110 I/026/07/0, Partial support of this work is provided by NASA ADP NNX07AT02G, CONACyT 83564, and PAPIITIN110209. These results are also based in part on observations obtained with XMM-Newton, an ESA Science Mission with instruments and contributions directly funded by ESA Member States and the USA (NASA).
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Istituto Nazionale di Astrofisica (Italian: National Institute for Astrophysics)PRIN/2007/
Agenzia Spaziale Italiana (Italian Space Agency)ASI/COFIS/WP3110 I/026/07/0
Consejo Nacional de Ciencia y Tecnología (CONACyT)83564
European Space Agency Member StatesUNSPECIFIED
Subject Keywords:surveys galaxies: active
Record Number:CaltechAUTHORS:20100416-154341585
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Official Citation:The [O iii] emission line luminosity function of optically selected type-2 AGN from zCOSMOSFormula A. Bongiorno, M. Mignoli, G. Zamorani, F. Lamareille, G. Lanzuisi, T. Miyaji, M. Bolzonella, C. M. Carollo, T. Contini, J. P. Kneib, O. Le Fèvre, S. J. Lilly, V. Mainieri, A. Renzini, M. Scodeggio, S. Bardelli, M. Brusa, K. Caputi, F. Civano, G. Coppa, O. Cucciati, S. de la Torre, L. de Ravel, P. Franzetti, B. Garilli, C. Halliday, G. Hasinger, A. M. Koekemoer, A. Iovino, P. Kampczyk, C. Knobel, K. Kova, J. -F. Le Borgne, V. Le Brun, C. Maier, A. Merloni, P. Nair, R. Pello, Y. Peng, E. Perez Montero, E. Ricciardelli, M. Salvato, J. Silverman, M. Tanaka, L. Tasca, L. Tresse, D. Vergani, E. Zucca, U. Abbas, D. Bottini, A. Cappi, P. Cassata, A. Cimatti, L. Guzzo, A. Leauthaud, D. Maccagni, C. Marinoni, H. J. McCracken, P. Memeo, B. Meneux, P. Oesch, C. Porciani, L. Pozzetti and R. Scaramella A&A 510 A56 (2010) DOI: 10.1051/0004-6361/200913229
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:18009
Deposited By: Ruth Sustaita
Deposited On:19 Apr 2010 16:48
Last Modified:07 Jul 2015 21:14

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