The Chandra Cosmos Legacy Survey: Overview and Point Source Catalog

Scientific paper - Original scientific paper

• Author: F. Civano
• Author: S. Marchesi
• Author: A. Comastri
• Author: M. C. Urry
• Author: M. Elvis
• Author: N. Cappelluti
• Author: S. Puccetti
• Author: M. Brusa
• Author: G. Zamorani
• Author: G. Hasinger
• Author: T. Aldcroft
• Author: D. M. Alexander
• Author: V. Allevato
• Author: H. Brunner
• Author: P. Capak
• Author: A. Finoguenov
• Author: F. Fiore
• Author: A. Fruscione
• Author: R. Gilli
• Author: K. Glotfelty
• Author: R. E. Griffiths
• Author: H. Hao
• Author: F. A. Harrison
• Author: K. Jahnke
• Author: J. Kartaltepe
• Author: A. Karim
• Author: S. M. LaMassa
• Author: G. Lanzuisi
• Author: T. Miyaji
• Author: P. Ranalli
• Author: M. Salvato
• Author: M. Sargent
• Author: N. J. Scoville
• Author: K. Schawinski
• Author: E. Schinnerer
• Author: J. Silverman
• Author: Vernesa Smolčić; MBZ: 336180
• Author: D. Stern
• Author: S. Toft
• Author: B. Trakhenbrot
• Author: E. Treister
• Author: C. Vignali
• Author's institution: University of Zagreb; Faculty of Science; (Department of Physics)
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Physics; Astronomy and Astrophysics

Abstract (english)

The COSMOS-Legacy survey is a 4.6 Ms Chandra program that has imaged 2.2 deg^2 of the COSMOS field with an effective exposure of ≃ 160 ks over the central 1.5 deg^2 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 erg cm^-2 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 >10^22 cm^‑2 from the hardness ratio (HR) is ∼50^+17_-16%. 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.

• Keywords (english): catalogs; cosmology: observations; galaxies: evolution; quasars: general; surveys; X-rays: general
• Language: english
• Publication type: Scientific paper - Original scientific paper
• Publication status: Published
• Peer review: Peer review - international
• Publication version: Published version
• Journal title: Astrophysical Journal
• Numbering: vol. 819, no. 1, pp. 62-80
• p-ISSN: 0004-637X
• e-ISSN: 1538-4357
• DOI: https://doi.org/10.3847/0004-637X/819/1/62
• URN:NBN: urn:nbn:hr:217:968544
• Publication: 2016
• Document URL: https://iopscience.iop.org/article/10.3847/0004-637X/819/1/62
• Type of resource: Text
• Access conditions: Open access
• Public note: © 2016. The American Astronomical Society. All rights reserved. Received 2015 July 31; accepted 2015 December 24; published 2016 February 29.
• Created on: 2020-02-23 10:41:08