The Chandra Deep Field-South survey: 4 Ms source catalogs

Y. Q. Xue, B. Luo, W. N. Brandt, F. E. Bauer, B. D. Lehmer, P. S. Broos, D. P. Schneider, D. M. Alexander, M. Brusa, A. Comastri, A. C. Fabian, R. Gilli, G. Hasinger, A. E. Hornschemeier, A. Koekemoer, T. Liu, V. Mainieri, M. Paolillo, D. A. Rafferty, P. RosatiO. Shemmer, J. D. Silverman, I. Smail, P. Tozzi, C. Vignali

Research output: Contribution to journalReview articlepeer-review

479 Scopus citations


We present source catalogs for the 4Ms Chandra Deep Field-South (CDF-S), which is the deepest Chandra survey to date and covers an area of 464.5 arcmin2. We provide a main Chandra source catalog, which contains 740 X-ray sources that are detected with WAVDETECT at a false-positive probability threshold of 10-5 in at least one of three X-ray bands (0.5-8keV, full band; 0.5-2keV, soft band; and 2-8keV, hard band) and also satisfy a binomial-probability source-selection criterion of P < 0.004 (i.e., the probability of sources not being real is less than 0.004); this approach is designed to maximize the number of reliable sources detected. A total of 300 main-catalog sources are new compared to the previous 2Ms CDF-S main-catalog sources. We determine X-ray source positions using centroid and matched-filter techniques and obtain a median positional uncertainty of ≈0″.42. We also provide a supplementary catalog, which consists of 36 sources that are detected with WAVDETECT at a false-positive probability threshold of 10 -5, satisfy the condition of 0.004 < P < 0.1, and have an optical counterpart with R < 24. Multiwavelength identifications, basic optical/infrared/radio photometry, and spectroscopic/photometric redshifts are provided for the X-ray sources in the main and supplementary catalogs. Seven hundred sixteen (≈97%) of the 740 main-catalog sources have multiwavelength counterparts, with 673 (≈94% of 716) having either spectroscopic or photometric redshifts. The 740 main-catalog sources span broad ranges of full-band flux and 0.5-8keV luminosity; the 300 new main-catalog sources span similar ranges although they tend to be systematically lower. Basic analyses of the X-ray and multiwavelength properties of the sources indicate that >75% of the main-catalog sources are active galactic nuclei (AGNs); of the 300 new main-catalog sources, about 35% are likely normal and starburst galaxies, reflecting the rise of normal and starburst galaxies at the very faint flux levels uniquely accessible to the 4Ms CDF-S. Near the center of the 4Ms CDF-S (i.e., within an off-axis angle of 3′), the observed AGN and galaxy source densities have reached 9800+1300- 1100deg-2 and 6900+1100- 900deg-2, respectively. Simulations show that our main catalog is highly reliable and is reasonably complete. The mean backgrounds (corrected for vignetting and exposure-time variations) are 0.063 and 0.178 counts Ms-1pixel-1 (for a pixel size of 0″.492) for the soft and hard bands, respectively; the majority of the pixels have zero background counts. The 4Ms CDF-S reaches on-axis flux limits of ≈3.2 × 10-17, 9.1 × 10 -18, and 5.5 × 10-17ergcm-2s-1 for the full, soft, and hard bands, respectively. An increase in the CDF-S exposure time by a factor of ≈2-2.5 would provide further significant gains and probe key unexplored discovery space.

Original languageEnglish (US)
Article number10
JournalAstrophysical Journal, Supplement Series
Issue number1
StatePublished - Jul 2011

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


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