THE CHANDRA COSMOS LEGACY SURVEY: OVERVIEW AND POINT SOURCE CATALOG

open42siThis work was supported in part by NASA Chandra grant number GO7-8136A (F.C., S.M., V.A., M.E., H.S.); PRIN-INAF 2014 "Windy Black Holes combing galaxy evolution" (A.C., M.B., G.L. and C.V.); the FP7 Career Integration Grant "eEASy": "Supermassive blackholes through cosmic time: from current surveys to eROSITA-Euclid Synergies"(CIG 321913; M.B. and G.L.); UNAM-DGAPA Grant PAPIIT IN104113 and CONACyT Grant Científica Básica #179662 (T.M.); Collaborative Research Council 956, sub-project A1, funded by the Deutsche Forschungsgemeinschaft (A.K.); NASA contract NAS8-03060 (T.A., A.F., K.G.); the Greek General Secretariat of Research and Technology in the framework of the Programme of Support of Postdoctoral Researchers (P.R.); NASA award NNX15AE61G (R.G.); the Science and Technology Facilities Council through grant code ST/I001573/1 (D.M.A.); the Swiss National Science Foundation Grant PP00P2_138979/1 (K.S.); the Center of Excellence in Astrophysics and Associated Technologies (PFB 06), by the FONDECYT regular grant 1120061 and by the CONICYT Anillo project ACT1101 (E.T.); the European Union's Seventh Framework Programme under grant agreements 337595 (ERC Starting Grant, "CoSMass") and 333654 (CIG, AGN feedback; V.S.). S.T. is part of The Dark Cosmology Centre, funded by the Danish National Research Foundation. B.T. is a Zwicky Fellow.The COSMOS-Legacy survey is a 4.6 Ms Chandra program that has imaged 2.2 deg2 of the COSMOS field with an effective exposure of ≃160 ks over the central 1.5 deg2 and of ≃80 ks in the remaining area. The survey is the combination of 56 new observations obtained as an X-ray Visionary Project with the previous C-COSMOS survey. We describe the reduction and analysis of the new observations and the properties of 2273 point sources detected above a spurious probability of 2 × 10-5. We also present the updated properties of the C-COSMOS sources detected in the new data. The whole survey includes 4016 point sources (3814, 2920 and 2440 in the full, soft, and hard band). The limiting depths are 2.2 × 10-16, 1.5 × 10-15, and 8.9 × 10-16 in the 0.5-2, 2-10, and 0.5-10 keV bands, respectively. The observed fraction of obscured active galactic nuclei with a column density >1022 cm-2 from the hardness ratio (HR) is ∼50-16+17%. Given the large sample we compute source number counts in the hard and soft bands, significantly reducing the uncertainties of 5%-10%. For the first time we compute number counts for obscured (HR > -0.2) and unobscured (HR < -0.2) sources and find significant differences between the two populations in the soft band. Due to the unprecedent large exposure, COSMOS-Legacy area is three times larger than surveys at similar depths and its depth is three times fainter than surveys covering similar areas. The area-flux region occupied by COSMOS-Legacy is likely to remain unsurpassed for years to come.openCivano, F.; Marchesi, S.; Comastri, A.; Urry, M.C.; Elvis, M.; Cappelluti, N.; Puccetti, S.; Brusa, M.; Zamorani, G.; Hasinger, G.; Aldcroft, T.; Alexander, D.M.; Allevato, V.; Brunner, H.; Capak, P.; Finoguenov, A.; Fiore, F.; Fruscione, A.; Gilli, R.; Glotfelty, K.; Griffiths, R.E.; Hao, H.; Harrison, F.A.; Jahnke, K.; Kartaltepe, J.; Karim, A.; Lamassa, S.M.; Lanzuisi, G.; Miyaji, T.; Ranalli, P.; Salvato, M.; Sargent, M.; Scoville, N.J.; Schawinski, K.; Schinnerer, E.; Silverman, J.; Smolcic, V.; Stern, D.; Toft, S.; Trakhenbrot, B.; Treister, E.; Vignali, C.Civano, F.; Marchesi, S.; Comastri, A.; Urry, M.C.; Elvis, M.; Cappelluti, N.; Puccetti, S.; Brusa, M.; Zamorani, G.; Hasinger, G.; Aldcroft, T.; Alexander, D.M.; Allevato, V.; Brunner, H.; Capak, P.; Finoguenov, A.; Fiore, F.; Fruscione, A.; Gilli, R.; Glotfelty, K.; Griffiths, R.E.; Hao, H.; Harrison, F.A.; Jahnke, K.; Kartaltepe, J.; Karim, A.; Lamassa, S.M.; Lanzuisi, G.; Miyaji, T.; Ranalli, P.; Salvato, M.; Sargent, M.; Scoville, N.J.; Schawinski, K.; Schinnerer, E.; Silverman, J.; Smolcic, V.; Stern, D.; Toft, S.; Trakhenbrot, B.; Treister, E.; Vignali, C