Large-scale clustering measurements with photometric redshifts: comparing the dark matter haloes of X-ray AGN, star-forming and passive galaxies at z ≈ 1



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Georgakakis, A. and Mountrichas, G. and Salvato, M and Rosario, D. and Pérez González, Pablo Guillermo and Lutz, D. and Nandra, K. and Coil, A. and Cooper, M. C. and Newman, J. A. and Berta, S. and Magnelli, B. and Popesso, P. and Pozzi, F. (2014) Large-scale clustering measurements with photometric redshifts: comparing the dark matter haloes of X-ray AGN, star-forming and passive galaxies at z ≈ 1. Monthly notices of the Royal Astronomical Society, 443 (4). pp. 3327-3340. ISSN 0035-8711

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We combine multi-wavelength data in the AEGIS-XD and C-COSMOS surveys to measure the typical dark matter halo mass of X-ray selected active galactic nuclei (AGN) [L_X(2–10 keV) > 10^42 erg s^− 1] in comparison with far-infrared selected star-forming galaxies detected in the Herschel/PEP survey (PACS Evolutionary Probe; L_IR > 10^11 L_⊙) and quiescent systems at z ≈ 1. We develop a novel method to measure the clustering of extragalactic populations that uses photometric redshift probability distribution functions in addition to any spectroscopy. This is advantageous in that all sources in the sample are used in the clustering analysis, not just the subset with secure spectroscopy. The method works best for large samples. The loss of accuracy because of the lack of spectroscopy is balanced by increasing the number of sources used to measure the clustering. We find that X-ray AGN, far-infrared selected star-forming galaxies and passive systems in the redshift interval 0.6 < z < 1.4 are found in haloes of similar mass, log M_DMH/(M_⊙ h^−1) ≈ 13.0. We argue that this is because the galaxies in all three samples (AGN, star-forming, passive) have similar stellar mass distributions, approximated by the J-band luminosity. Therefore, all galaxies that can potentially host X-ray AGN, because they have stellar masses in the appropriate range, live in dark matter haloes of log M_DMH/(M_⊙ h^−1) ≈ 13.0 independent of their star formation rates. This suggests that the stellar mass of X-ray AGN hosts is driving the observed clustering properties of this population. We also speculate that trends between AGN properties (e.g. luminosity, level of obscuration) and large-scale environment may be related to differences in the stellar mass of the host galaxies.

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© 2014 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.
The authors are grateful to the anonymous referee for helpful comments, M. Krumpe for discussions that improved this paper, J. Aird for providing optical identifications of X-ray sources and O. Ilbert for making available photometric redshift PDFs for galaxies in the COSMOS survey field. GM acknowledges financial support from the Marie-Curie Reintegration Grant PERG03-GA-2008-230644 and the THALES project 383549, which is jointly funded by the European Union and the Greek Government in the framework of the programme 'Education and lifelong learning'. PGP-G acknowledges support from the Spanish Programa Nacional de Astronomía y Astrofísica under grant AYA2012-31277. This work has made use of the Rainbow Cosmological Surveys Database, which is operated by the Universidad Complutense de Madrid (UCM), partnered with the University of California Observatories at Santa Cruz (UCO/Lick,UCSC). Funding for the DEEP2 Galaxy Redshift Survey has been provided in part by NSF grants AST95-09298, AST-0071048, AST-0071198, AST-0507428, and AST-0507483 as well as NASA LTSA grant NNG04GC89G. Funding for the DEEP3 Galaxy Redshift Survey has been provided by NSF grants AST-0808133, AST-0807630, and AST-0806732. Based on observations obtained with MegaPrime/MegaCam, a joint project of CFHT and CEA/DAPNIA, at the Canada France Hawaii Telescope which is operated by the National Research Council (NRC) of Canada, the Institut National des Sciences de l’Univers of the Centre National de la Recherche Scientifique (CNRS) of France, and the University Hawaii. This work is based in part on data products produced at TERAPIX and the Canadian Astronomy Data Centre as part of the CFHTLS, a collaborative project of NRC and CNRS.

Uncontrolled Keywords:Active galactic nucleus; Supermassive black-holes; Extended groth strip; Stellar mass; Host galaxies; Observational constraints; Spitzer/Irac sources; Luminosity function; Formation rates; Goods-herschel
Subjects:Sciences > Physics > Astrophysics
Sciences > Physics > Astronomy
ID Code:38303
Deposited On:30 Jun 2016 14:58
Last Modified:10 Dec 2018 15:05

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