Otelo survey: Deep BVRI broadband photometry of the groth strip. II. Optical properties of X-ray emitters



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Pović, M. and Sánchez Portal, M. and Pérez García, A. M. and Bongiovanni, A. and Cepa, J. and Alfaro, E. and Castañeda, H. and Fernández Lorenzo, M. and Gallego Maestro, Jesús and González Serrano, J. I. and González, J. J. and Lara López, M. A. (2009) Otelo survey: Deep BVRI broadband photometry of the groth strip. II. Optical properties of X-ray emitters. Astrophysical journal, 706 (1). pp. 810-823. ISSN 0004-637X

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Official URL: http://dx.doi.org/10.1088/0004-637X/706/1/810


The Groth field is one of the sky regions that will be targeted by the OSIRIS Tunable Filter Emission Line Object survey in the optical 820 nm and 920 nm atmospheric windows. In the present paper, public Chandra X-ray data with total exposure time of 200 ks are analyzed and combined with optical broadband data of the Groth field, in order to study a set of optical structural parameters of the X-ray emitters and its relation with X-ray properties. To this aim, we processed the raw, public X-ray data using the Chandra Interactive Analysis of Observations, and determined and analyzed different structural parameters, in order to produce a morphological classification of X-ray sources. We present the morphology of 340 X-ray emitters with optical counterpart detected. Objects have been classified by X-ray type using a diagnostic diagram relating X-ray-to-optical ratio (X/O) to hardness ratio. We did not find any clear correlation between X-ray and morphological types. We analyzed the angular clustering of X-ray sources with optical counterpart using two-point correlation functions. A significant positive angular clustering was obtained from a preliminary analysis of four subsamples of the X-ray sources catalog. The clustering signal of the optically extended counterparts is similar to that of strongly clustered populations like red and very red galaxies, suggesting that the environment plays an important role in active galactic nuclei phenomena. Finally, we combined optical structural parameters with other X-ray and optical properties, and we confirmed an anticorrelation between the X/O ratio and the Abraham concentration index, which might suggest that early-type galaxies have lower Eddington rates than those of late-type galaxies.

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© 2009. The American Astronomical Society. We thank the anonymous referee for a number of valuable comments and suggestions which contributed to improve the quality of this paper. We would also like to thank Laura Tomas who kindly provided us with her software for diagnosis of hardness ratios using model grids. This work was supported by the Spanish Plan Nacional de Astronomía y Astrofísica under grants AYA2006-2358 and AYA2008-06311-C02-01. J.I.G.-S. and J.G. acknowledge financial support from the Spanish Ministerio de Educación y Ciencia under grants AYA2008-06311-C02-02 and AYA2006-2358, respectively. This research has made use of software provided by the Chandra X-ray Center (CXC) in the application packages CIAO and ChIPS. IRAF is distributed by the National Optical Astronomy Observatory, which is operated by the Association of Universities for Research in Astronomy (AURA) under cooperative agreement with the National Science Foundation. This publication makes use of data products from the Two Micron All Sky Survey, which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center California Institute of Technology, funded by the National Aeronautics and Space Administration and the National Science Foundation. We acknowledge support from the Faculty of the European Space Astronomy Centre (ESAC).

Uncontrolled Keywords:Active galactic nuclei; Large-scale structure; Angular-correlation function; Newton serendipitous survey; Host galaxy morphologies; Supermassive black-hole; France redshift survey; Field north survey; Hellas2xmm survey; Number counts
Subjects:Sciences > Physics > Astrophysics
Sciences > Physics > Astronomy
ID Code:34137
Deposited On:05 Nov 2015 13:25
Last Modified:10 Dec 2018 15:05

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