1. The Chandra COSMOS-Legacy Survey: Source X-Ray Spectral Properties
- Author
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John D. Silverman, Kazushi Iwasawa, Giorgio Lanzuisi, Francesca Civano, C. M. Urry, G. Zamorani, Andrea Comastri, Stefano Marchesi, Richard E. Griffiths, Piero Ranalli, Viola Allevato, Mara Salvato, Takamitsu Miyaji, Hyewon Suh, Ezequiel Treister, Kevin Schawinski, Cristian Vignali, Department of Physics, ITA, USA, DEU, ESP, CHL, FIN, JPN, MEX, SWE, CHE, Universitat de Barcelona, Marchesi, S., Lanzuisi, G., Civano, F., Iwasawa, K., Suh, H., Comastri, A., Zamorani, G., Allevato, V., Griffiths, R., Miyaji, T., Ranalli, P., Salvato, M., Schawinski, K., Silverman, J., Treister, E., Urry, C.M., Vignali, C., and Urry, C. M.
- Subjects
galaxie [X-rays] ,ACTIVE GALACTIC NUCLEI ,COMPTON-THICK AGN ,Photon ,Active galactic nucleus ,HEAVILY OBSCURED AGN ,Astrophysics::High Energy Astrophysical Phenomena ,galaxies: active ,nuclei [galaxies] ,FOS: Physical sciences ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,01 natural sciences ,Beta ray spectrometry ,0103 physical sciences ,STAR-FORMING GALAXIES ,Emission spectrum ,DEEP FIELD-SOUTH ,Absorption (electromagnetic radiation) ,SEYFERT 2 GALAXIES ,010303 astronomy & astrophysics ,XMM-NEWTON OBSERVATIONS ,PHOTOMETRIC REDSHIFTS ,Astrophysics::Galaxy Astrophysics ,Physics ,EVOLUTION SURVEY COSMOS ,Cosmologia ,010308 nuclear & particles physics ,Star formation ,ABSORBING COLUMN DENSITIES ,X-ray ,Astronomy and Astrophysics ,Astronomy and Astrophysic ,115 Astronomy, Space science ,Astrophysics - Astrophysics of Galaxies ,Redshift ,Galaxy ,Espectrometria de raigs beta ,Cosmology ,X-rays: galaxies ,Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) ,active [galaxies] ,galaxies: nuclei - Abstract
We present the X-ray spectral analysis of the 1855 extragalactic sources in the Chandra COSMOS-Legacy survey catalog having more than 30 net counts in the 0.5-7 keV band. 38% of the sources are optically classified Type 1 active galactic nuclei (AGN), 60% are Type 2 AGN and 2% are passive, low-redshift galaxies. We study the distribution of AGN photon index and of the intrinsic absorption N(H,z) based on the sources optical classification: Type 1 have a slightly steeper mean photon index than Type 2 AGN, which on the other hand have average intrinsic absorption ~3 times higher than Type 1 AGN. We find that ~15% of Type 1 AGN have N(H,z)>1E22 cm^(-2), i.e., are obscured according to the X-ray spectral fitting; the vast majority of these sources have L(2-10keV)>$1E44 erg/s. The existence of these objects suggests that optical and X-ray obscuration can be caused by different phenomena, the X-ray obscuration being for example caused by dust-free material surrounding the inner part of the nuclei. ~18% of Type 2 AGN have N(H,z), Comment: 23 pages, 16 figures. Accepted for publication on ApJ
- Published
- 2016