THE EXTENDED CHANDRA DEEP FIELD-SOUTH SURVEY: OPTICAL PROPERTIES OF X-RAY DETECTED SOURCES

摘要

The Extended Chandra Deep Field-South (E-CDF-S) survey consists of 4 Chandra ACIS-I pointings and covers ≈1100 square arcminutes (≈0.3deg{sup}2) centered on the original CDF-S field to a depth of approximately 228ks (PI: Niel Brandt; Lehmer et al., 2005). This is the largest Chandra survey ever conducted at such depth. In our analysis (Virani et al., 2005), we detect 651 unique sources - 587 using a conservative source detection limit and 64 using a lower source detection limit. Of these 651 sources, 561 are detected in the full 0.5-8.0keV band, 529 in the soft 0.5-2.0keV band, and 335 in the hard 2.0-8.0keV band. For point sources near the aim point, the limiting fluxes are approximately 1.7×10{sup}(-16)erg cm{sup}(-2) s{sup}(-1) and 3.9×10{sup}(-16)erg cm{sup}(-2) s{sup}(-1) in the 0.5-2.0keV and 2.0-8.0keV bands, respectively. We present the optical properties of these X-ray sources, specifically the R-band magnitude distribution and a preliminary spectroscopic redshift distribution. One exciting result is the discovery of 7 new Extreme X-ray-to-Optical flux ratio objects (EXOs) found in the E-CDF-S field.