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Chandra COSMOS (C-COSMOS) Survey Optical/IR Counterparts Catalog

Metadata Updated: September 19, 2025

The Chandra COSMOS Survey (C-COSMOS) is a large, 1.8-Ms, Chandra program that has imaged the central 0.9 deg<sup>2</sup> of the COSMOS field down to limiting depths of 1.9 x 10<sup>-16</sup> erg/cm<sup>2</sup>/s in the soft (0.5-2 keV) band, 7.3 x 10<sup>-16</sup> erg/cm<sup>2</sup>/s in the hard (2-10 keV) band, and 5.7 x 10<sup>-16</sup> erg/cm<sup>2</sup>/s in the full (0.5-10 keV) band. In this Paper III of the series of papers on this survey, the authors report the i, K, and 3.6-um identifications of the 1761 X-ray point sources. They use the likelihood ratio technique to derive the association of optical/infrared counterparts for 97% of the X-ray sources. For most of the remaining 3%, the presence of multiple counterparts or the faintness of the possible counterpart prevented a unique association. For only 10 X-ray sources, they were not able to associate a counterpart, mostly due to the presence of a very bright field source close by. Only two sources are truly empty fields. The full catalog, including spectroscopic and photometric redshifts and classification described here in detail, is available herein. See also the related table <a href="ccosmoscat.html">CCOSMOSCAT</a> for the the surveyed X-ray point sources. This table was created by the HEASARC in December 2012, based on the <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJS/201/30">CDS Catalog J/ApJS/201/30</a> file catalog.dat. This is a service provided by NASA HEASARC .

Access & Use Information

Public: This dataset is intended for public access and use. License: No license information was provided. If this work was prepared by an officer or employee of the United States government as part of that person's official duties it is considered a U.S. Government Work.

Downloads & Resources

Dates

Metadata Created Date April 11, 2025
Metadata Updated Date September 19, 2025

Metadata Source

Harvested from NASA Data.json

Additional Metadata

Resource Type Dataset
Metadata Created Date April 11, 2025
Metadata Updated Date September 19, 2025
Publisher High Energy Astrophysics Science Archive Research Center
Maintainer
Identifier ivo://nasa.heasarc/ccosmosoid
Data Last Modified 2025-09-10
Category Astrophysics
Public Access Level public
Bureau Code 026:00
Metadata Context https://project-open-data.cio.gov/v1.1/schema/catalog.jsonld
Schema Version https://project-open-data.cio.gov/v1.1/schema
Catalog Describedby https://project-open-data.cio.gov/v1.1/schema/catalog.json
Harvest Object Id 3b8e1896-7c44-4e72-8bd1-8230988cd14a
Harvest Source Id 58f92550-7a01-4f00-b1b2-8dc953bd598f
Harvest Source Title NASA Data.json
Homepage URL https://heasarc.gsfc.nasa.gov/W3Browse/all/ccosmosoid.html
Program Code 026:000
Source Datajson Identifier True
Source Hash fe887b70fb8106d77ba860ea9581730fd9264ae2716155424eb736da818e165c
Source Schema Version 1.1

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