THE CHANDRA COSMOS LEGACY SURVEY: OPTICAL/IR IDENTIFICATIONS
By S. Marchesi, F. Civano, M. Elvis, Mara Salvato, M. Brusa, A. Comastri, R. Gilli, G. Hasinger, G. Lanzuisi, T. Miyaji and 20 more. 2015
176 citations recorded by the source corpus.
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 ≃54% 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.
Subfields: Astronomy and Astrophysics, Atomic and Molecular Physics, and Optics
View Paper: https://www.semanticscholar.org/paper/02153226b011b88143a7aa6c422c1bc35ae3a283
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Citations in the corpus
- The many flavours of photometric redshifts (2018, methodology): “There, we show the difference between photo-z computed using either AGN [104] or galaxy [88] templates, for a sample of 1672 X-ray selected AGN with a secure spec-z from the Legacy Chandra COSMOS field [105].”
- AGN wind scaling relations and the co-evolution of black holes and galaxies (2017, methodology): “At z > 3 we used the Fiore et al. (2012), Ueda et al. (2014), Georgakakis et al. (2015), Aird et al. (2015), Kalfountzou et al. (2014), Vito et al. (2014), Marchesi et al. (2016), and Puccetti et al. (in prep.)”
- Active galactic nuclei: what’s in a name? (2017, background): “), combined with the COSMOS multi-wavelength data (Laigle et al. 2016; Marchesi et al. 2016), yield a stronger cosmic evolution for”
- x-cigale: fitting AGN/galaxy SEDs from X-ray to infrared (2020, background): “We adopt the redshift measurements from Marchesi et al. (2016).”
- THE COSMOS2015 CATALOG: EXPLORING THE 1 < z < 6 UNIVERSE WITH HALF A MILLION GALAXIES (2016, background): “X-ray photometry The Chandra COSMOS-Legacy Survey (Civano et al. 2016; Marchesi et al. 2016) contains 4016 X-ray sources down to a flux limit of fX '2× 10−16 erg s−1 cm−2 in the 0.5-2 keV band: 3755 of these sources lie inside the UltraVISTA field of view.”
- The DEIMOS 10K Spectroscopic Survey Catalog of the COSMOS Field (2018, methodology): “15 http://www2.keck.hawaii.edu/inst/deimos/dsim.html and Chandra (e.g., Civano et al. 2012; Marchesi et al. 2016a, 2016b) surveys (PI: Hasinger); this is the “X-ray” subsample.”
- The COSMOS2015 galaxy stellar mass function . Thirteen billion years of stellar mass assembly in ten snapshots (2017, background): “They increase the exponential tail of our SMF at least at z 6 3, while at higher redshift the number of sources detected by Chandra or XMM is too small (Fig.”