The Chandra deep field-south survey: 2 Ms source catalogs

B. Luo, F. E. Bauer, W. N. Brandt, D. M. Alexander, B. D. Lehmer, D. P. Schneider, M. Brusa, A. Comastri, A. C. Fabian, A. Finoguenov, R. Gilli, G. Hasinger, A. E. Hornschemeier, A. Koekemoer, V. Mainieri, M. Paolillo, P. Rosati, O. Shemmer, J. D. Silverman, I. SmailA. T. Steffen, C. Vignali

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Abstract

We present point-source catalogs for the ≈2 Ms exposure of the Chandra Deep Field-South (CDF-S); this is one of the two most sensitive X-ray surveys ever performed. The survey covers an area of ≈436 arcmin2 and reaches on-axis sensitivity limits of ≈1.9 × 10-17 and ≈1.3 × 10-16 ergs cm-2 s-1 for the 0.5-2.0 and 2-8 keV bands, respectively. Four hundred and sixty-two X-ray point sources are detected in at least one of three X-ray bands that were searched; 135 of these sources are newcompared to the previous ≈1 Ms CDF-S detections. Source positions are determined using centroid and matched-filter techniques; the median positional uncertainty is ≈0.36″. The X-ray-to-optical flux ratios of the newly detected sources indicate a variety of source types; ≈55% of them appear to be active galactic nuclei, while ≈45% appear to be starburst and normal galaxies. In addition to the main Chandra catalog, we provide a supplementary catalog of 86 X-ray sources in the ≈2 Ms CDF-S footprint that was created by merging the ≈250 ks Extended Chandra Deep Field-South with the CDF-S; this approach provides additional sensitivity in the outer portions of the CDF-S. A second supplementary catalog that contains 30 X-ray sources was constructed by matching lower significance X-ray sources to bright optical counterparts (R < 23.8); the majority of these sources appear to be starburst and normal galaxies. The total number of sources in the main and supplementary catalogs is 578. Optical R-band counterparts and basic optical and infrared photometry are provided for the X-ray sources in the main and supplementary catalogs. We also include existing spectroscopic redshifts for 224 of the X-ray sources. The average backgrounds in the 0.5-2.0 and 2-8 keV bands are 0.066 and 0.167 counts Ms-1 pixel-1, respectively, and the background counts follow Poisson distributions. The effective exposure times and sensitivity limits of the CDF-S are now comparable to those of the ≈2 Ms Chandra Deep Field-North (CDF-N). We also present cumulative number counts for the main catalog and compare the results to those for the CDF-N. The soft-band number counts for these two fields agree well with each other at fluxes higher than ≈2 × 10-16 ergs cm-2 s -1, while the CDF-S number counts are up to ≈25% smaller than those for the CDF-N at fluxes below ≈2 × 10-16 ergs cm -2 s-1 in the soft band and ≈2 × 10-15 ergs cm-2 s-1 in the hard band, suggesting small field-to-field variations.

Original languageEnglish (US)
Pages (from-to)19-36
Number of pages18
JournalAstrophysical Journal, Supplement Series
Volume179
Issue number1
DOIs
StatePublished - Nov 1 2008

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All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Luo, B., Bauer, F. E., Brandt, W. N., Alexander, D. M., Lehmer, B. D., Schneider, D. P., Brusa, M., Comastri, A., Fabian, A. C., Finoguenov, A., Gilli, R., Hasinger, G., Hornschemeier, A. E., Koekemoer, A., Mainieri, V., Paolillo, M., Rosati, P., Shemmer, O., Silverman, J. D., ... Vignali, C. (2008). The Chandra deep field-south survey: 2 Ms source catalogs. Astrophysical Journal, Supplement Series, 179(1), 19-36. https://doi.org/10.1086/591248