The Chandra COSMOS Survey. I. overview and point source catalog

Martin Elvis, Francesca Civano, Cristian Vignali, Simonetta Puccetti, Fabrizio Fiore, Nico Cappelluti, T. L. Aldcroft, Antonella Fruscione, G. Zamorani, Andrea Comastri, Marcella Brusa, Roberto Gilli, Takamitsu Miyaji, Francesco Damiani, Anton M. Koekemoer, Alexis Finoguenov, Hermann Brunner, C. M. Urry, John Silverman, Vincenzo MainieriGuenther Hasinger, Richard Griffiths, Marcella Carollo, Heng Hao, Luigi Guzzo, Andrew Blain, Daniela Calzetti, C. Carilli, Peter Capak, Stefano Ettori, Giuseppina Fabbiano, Chris Impey, Simon Lilly, Bahram Mobasher, Michael Rich, Mara Salvato, D. B. Sanders, Eva Schinnerer, N. Scoville, Patrick Shopbell, James E. Taylor, Yoshiaki Taniguchi, Marta Volonteri

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374 Scopus citations


The Chandra COSMOS Survey (C-COSMOS) is a large, 1.8 Ms, Chandra program that has imaged the central 0.5 deg2 of the COSMOS field (centered at 10h, +02o) with an effective exposure of ∼160 ks, and an outer 0.4 deg2 area with an effective exposure of ∼80 ks. The limiting source detection depths are 1.9 × 10-16 erg cm -2 s-1 in the soft (0.5-2 keV) band, 7.3 × 10 -16 erg cm-2 s-1 in the hard (2-10 keV) band, and 5.7 × 10-16 erg cm-2 s-1 in the full (0.5-10 keV) band. Here we describe the strategy, design, and execution of the C-COSMOS survey, and present the catalog of 1761 point sources detected at a probability of being spurious of <2 × 10-5 (1655 in the full, 1340 in the soft, and 1017 in the hard bands). By using a grid of 36 heavily (∼50%) overlapping pointing positions with the ACIS-I imager, a remarkably uniform (12%) exposure across the inner 0.5 deg2 field was obtained, leading to a sharply defined lower flux limit. The widely different point-spread functions obtained in each exposure at each point in the field required a novel source detection method, because of the overlapping tiling strategy, which is described in a companion paper. This method produced reliable sources down to a 7-12 counts, as verified by the resulting logN-logS curve, with subarcsecond positions, enabling optical and infrared identifications of virtually all sources, as reported in a second companion paper. The full catalog is described here in detail and is available online.

Original languageEnglish (US)
Pages (from-to)158-171
Number of pages14
JournalAstrophysical Journal, Supplement Series
Issue number1
StatePublished - 2009


  • Catalogs
  • Cosmology: observations
  • Galaxies: evolution
  • Quasars: general
  • Surveys
  • X-rays: general

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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  • Chandra COSMOS survey I.

    Elvis, M. (Creator), Civano, F. (Creator), Vignali, C. (Creator), Puccetti, S. (Creator), Fiore, F. (Creator), Cappelluti, N. (Creator), Aldcroft, T. L. (Creator), Fruscione, A. (Creator), Zamorani, G. (Creator), Comastri, A. (Creator), Brusa, M. (Creator), Gilli, R. (Creator), Miyaji, T. (Creator), Damiani, F. (Creator), Koekemoer, A. M. (Creator), Finoguenov, A. (Creator), Brunner, H. (Creator), Urry, C. M. (Creator), Silverman, J. (Creator), Mainieri, V. (Creator), Hasinger, G. (Creator), Griffiths, R. (Creator), Carollo, M. (Creator), Hao, H. (Creator), Guzzo, L. (Creator), Blain, A. (Creator), Calzetti, D. (Creator), Carilli, C. (Creator), Capak, P. (Creator), Ettori, S. (Creator), Fabbiano, G. (Creator), Impey, C. D. (Creator), Lilly, S. (Creator), Mobasher, B. (Creator), Rich, M. (Creator), Salvato, M. (Creator), Sanders, D. B. (Creator), Schinnerer, E. (Creator), Scoville, N. (Creator), Shopbell, P. (Creator), Taylor, J. E. (Creator), Taniguchi, Y. (Creator), Volonteri, M. (Creator), Vignali, C. (Creator), Gilli, R. (Creator), Miyaji, T. (Creator), Silverman, J. (Creator), Guzzo, L. (Creator), Carilli, C. (Creator), Capak, P. (Creator), Sanders, D. B. (Creator) & Schinnerer, E. (Creator), Centre de Donnees Strasbourg (CDS), 2010


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