The Chandra COSMOS Survey, I: Overview and Point Source Catalog
astro-ph.CO
/ Authors
Martin Elvis, Francesca Civano, Cristian Vignali, Simonetta Puccetti, Fabrizio Fiore, Nico Cappelluti, T. L. Aldcroft, Antonella Fruscione, G. Zamorani, Andrea Comastri
and 33 more authors
Marcella Brusa, Roberto Gilli, Takamitsu Miyaji, Francesco Damiani, Anton Koekemoer, Alexis Finoguenov, Hermann Brunner, C. M. Urry, John Silverman, Vincenzo Mainieri, Guenther 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
/ Abstract
The Chandra COSMOS Survey (C-COSMOS) is a large, 1.8 Ms, Chandra} program that has imaged the central 0.5 sq.deg of the COSMOS field (centered at 10h, +02deg) with an effective exposure of ~160ksec, and an outer 0.4sq.deg. area with an effective exposure of ~80ksec. The limiting source detection depths are 1.9e-16 erg cm(-2) s(-1) in the Soft (0.5-2 keV) band, 7.3e(-16) erg cm^-2 s^-1 in the Hard (2-10 keV) band, and 5.7e(-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 <2e(-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 (to 12%) exposure across the inner 0.5 sq.deg field was obtained, leading to a sharply defined lower flux limit. The widely different PSFs 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. (Puccetti et al. Paper II). This method produced reliable sources down to a 7-12 counts, as verified by the resulting logN-logS curve, with sub-arcsecond positions, enabling optical and infrared identifications of virtually all sources, as reported in a second companion paper (Civano et al. Paper III). The full catalog is described here in detail, and is available on-line.