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The CHANDRA COSMOS Legacy Survey: Optical / IR Identifications

Marchesi, S. and Civano, F. and Elvis, M. and Salvato, M. and Brusa, M. and Comastri, A. and Gilli, R. and Hasinger, G. and Lanzuisi, G. and Miyaji, T. and Treister, E. and Urry, C. M. and Vignali, C. and Zamorani, G. and Allevato, V. and Cappelluti, N. and Cardamone, C. and Finoguenov, A. and Griffiths, R. E. and Karim, A. and Laigle, C. and LaMassa, S. M. and Jahnke, K. and Ranalli, P. and Schawinski, K. and Schinnerer, E. and Silverman, J. D. and Smolčić, V. and Suh, H. and Trakhtenbrot, B. (2016) The CHANDRA COSMOS Legacy Survey: Optical / IR Identifications. Astrophysical Journal, 817 (1). Art No 34. ISSN 0004-637X. doi:10.3847/0004-637X/817/1/34.

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We present the catalog of optical and infrared counterparts of the Chandra COSMOS-Legacy Survey, a 4.6 Ms Chandra program on the 2.2 deg2 of the COSMOS field, combination of 56 new overlapping observations obtained in Cycle 14 with the previous C-COSMOS survey. In this Paper we report the i, K, and 3.6 μm identifications of the 2273 X-ray point sources detected in the new Cycle 14 observations. We use the likelihood ratio technique to derive the association of optical/infrared (IR) counterparts for 97% of the X-ray sources. We also update the information for the 1743 sources detected in C-COSMOS, using new K and 3.6 μm information not available when the C-COSMOS analysis was performed. The final catalog contains 4016 X-ray sources, 97% of which have an optical/IR counterpart and a photometric redshift, while sime54% of the sources have a spectroscopic redshift. The full catalog, including spectroscopic and photometric redshifts and optical and X-ray properties described here in detail, is available online. We study several X-ray to optical (X/O) properties: with our large statistics we put better constraints on the X/O flux ratio locus, finding a shift toward faint optical magnitudes in both soft and hard X-ray band. We confirm the existence of a correlation between X/O and the the 2–10 keV luminosity for Type 2 sources. We extend to low luminosities the analysis of the correlation between the fraction of obscured AGNs and the hard band luminosity, finding a different behavior between the optically and X-ray classified obscured fraction.

Item Type:Article
Related URLs:
URLURL TypeDescription
Marchesi, S.0000-0001-5544-0749
Civano, F.0000-0002-2115-1137
Salvato, M.0000-0001-7116-9303
Brusa, M.0000-0002-5059-6848
Comastri, A.0000-0003-3451-9970
Hasinger, G.0000-0002-0797-0646
Lanzuisi, G.0000-0001-9094-0984
Treister, E.0000-0001-7568-6412
Urry, C. M.0000-0002-0745-9792
Vignali, C.0000-0002-8853-9611
Finoguenov, A.0000-0002-4606-5403
LaMassa, S. M.0000-0002-5907-3330
Jahnke, K.0000-0003-3804-2137
Schawinski, K.0000-0001-5464-0888
Schinnerer, E.0000-0002-3933-7677
Silverman, J. D.0000-0002-0000-6977
Smolčić, V.0000-0002-3893-8614
Suh, H.0000-0002-2536-1633
Trakhtenbrot, B.0000-0002-3683-7297
Additional Information:© 2016 The American Astronomical Society.
Issue or Number:1
Record Number:CaltechAUTHORS:20170628-144219700
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:78673
Deposited By: Joy Painter
Deposited On:28 Jun 2017 21:50
Last Modified:15 Nov 2021 17:42

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