The CHANDRA COSMOS Legacy Survey: Optical / IR Identifications
- Creators
- Marchesi, S.
- Civano, F.
- Elvis, M.
- Salvato, M.
- Brusa, M.
- Comastri, A.
- Gilli, R.
- Hasinger, G.
- Lanzuisi, G.
- Miyaji, T.
- Treister, E.
- Urry, C. M.
- Vignali, C.
- Zamorani, G.
- Allevato, V.
- Cappelluti, N.
- Cardamone, C.
- Finoguenov, A.
- Griffiths, R. E.
- Karim, A.
- Laigle, C.
- LaMassa, S. M.
- Jahnke, K.
- Ranalli, P.
- Schawinski, K.
- Schinnerer, E.
- Silverman, J. D.
- Smolčić, V.
- Suh, H.
- Trakhtenbrot, B.
Abstract
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.
Additional Information
© 2016 The American Astronomical Society.Additional details
- Eprint ID
- 78673
- DOI
- 10.3847/0004-637X/817/1/34
- Resolver ID
- CaltechAUTHORS:20170628-144219700
- Created
-
2017-06-28Created from EPrint's datestamp field
- Updated
-
2021-11-15Created from EPrint's last_modified field
- Caltech groups
- SPLASH, COSMOS