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arXiv · 1302.1062

The Chandra-COSMOS survey IV: X-ray spectra of the bright sample

G. Lanzuisi·F. Civano·M. Elvis·M. Salvato·G. Hasinger·C. Vignali·G. Zamorani·T. Aldcroft·M. Brusa·A. Comastri·F. Fiore·A. Fruscione·R. Gilli·L. C. Ho·V. Mainieri·A. Merloni·A. Siemiginowska
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Abstract

We present the X-ray spectral analysis of the 390 brightest extragalactic sources in the Chandra-COSMOS catalog, showing at least 70 net counts in the 0.5-7 keV band. This sample has a 100% completeness in optical-IR identification, with 75% of the sample having a spectroscopic redshift and 25% a photometric redshift. Our analysis allows us to accurately determine the intrinsic absorption, the broad band continuum shape (Γ) and intrinsic L(2-10) distributions, with an accuracy better than 30% on the spectral parameters for 95% of the sample. The sample is equally divided in type-1 (49.7%) and type-2 AGN (48.7%) plus few passive galaxies at low z. We found a significant difference in the distribution of Γ of type-1 and type-2, with small intrinsic dispersion, a weak correlation of Γ with L(2-10) and a large population (15% of the sample) of high luminosity, highly obscured (QSO2) sources. The distribution of the X ray/Optical flux ratio (Log(FX /Fi)) for type-1 is narrow (0 < X/O < 1), while type-2 are spread up to X/O = 2. The X/O correlates well with the amount of X-ray obscuration. Finally, a small sample of Compton thick candidates and peculiar sources is presented. In the appendix we discuss the comparison between Chandra and XMM-Newton spectra for 280 sources in common. We found a small systematic difference, with XMM-Newton spectra that tend to have softer power-laws and lower obscuration.

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G. Lanzuisi, F. Civano, M. Elvis, M. Salvato, G. Hasinger, C. Vignali, G. Zamorani, T. Aldcroft, M. Brusa, A. Comastri, F. Fiore, A. Fruscione, R. Gilli, L. C. Ho, V. Mainieri, A. Merloni, A. Siemiginowska. 2013-02-07. The Chandra-COSMOS survey IV: X-ray spectra of the bright sample. https://doi.org/10.1093/mnras%2Fstt222

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