We present point-source catalogs for the approximate to 2Ms 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 approximate to 436 arcmin(2) and reaches on-axis sensitivity limits of approximate to 1: 9; 10(-17) and approximate to 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 new compared to the previous approximate to 1 Ms CDF-S detections. Source positions are determined using centroid and matched-filter techniques; the median positional uncertainty is approximate to 0.36 ''. The X-ray-to-optical flux ratios of the newly detected sources indicate a variety of source types; approximate to 55% of them appear to be active galactic nuclei, while approximate to 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 approximate to 2Ms CDF-S footprint that was created by merging the approximate to 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 2Y8 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 approximate to 2Ms 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 approximate to 2; 10(-16) ergs cm(-2) s(-1), while the CDF-S number counts are up to approximate to 25% smaller than those for the CDF-N at fluxes below approximate to 2; 10(-16) ergs cm(-2) s(-1) in the soft band and approximate to 2; 10(-15) ergs cm(-2) s(-1) in the hard band, suggesting small field-to-field variations.
THE CHANDRA DEEP FIELD-SOUTH SURVEY: 2 Ms SOURCE CATALOGS
ROSATI, Piero;
2008
Abstract
We present point-source catalogs for the approximate to 2Ms 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 approximate to 436 arcmin(2) and reaches on-axis sensitivity limits of approximate to 1: 9; 10(-17) and approximate to 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 new compared to the previous approximate to 1 Ms CDF-S detections. Source positions are determined using centroid and matched-filter techniques; the median positional uncertainty is approximate to 0.36 ''. The X-ray-to-optical flux ratios of the newly detected sources indicate a variety of source types; approximate to 55% of them appear to be active galactic nuclei, while approximate to 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 approximate to 2Ms CDF-S footprint that was created by merging the approximate to 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 2Y8 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 approximate to 2Ms 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 approximate to 2; 10(-16) ergs cm(-2) s(-1), while the CDF-S number counts are up to approximate to 25% smaller than those for the CDF-N at fluxes below approximate to 2; 10(-16) ergs cm(-2) s(-1) in the soft band and approximate to 2; 10(-15) ergs cm(-2) s(-1) in the hard band, suggesting small field-to-field variations.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
