EXOs and Obscured AGN in the MUSYC Survey
Abstract
With its deep near-infrared imaging, the MUltiwavelength Survey by Yale-Chile (MUSYC) is ideal for finding EXOs, i.e., objects with Extreme X-ray to Optical flux ratios. Defining an EXO as an X-ray source with no optical counterpart down to R ∼27 but a reasonably bright K-band counterpart (K<22 AB), EXOs are very red with R-K >5. We describe 7 EXOs found in the Extended Chandra Deep Field-South (ECDFS), a wide-deep public survey with area ∼1100 square arcminutes ( ∼0.3 deg2) and depth ∼228 ks. Our X-ray catalog reaches X-ray fluxes of ∼1.7 x 10-16 erg cm-2 s-1 and ∼3.9 x 10-16 erg cm-2 s-1 in the 0.5--2.0 keV and 2.0--8.0 keV bands, respectively, and our optical and near-IR imaging reaches R=27 (AB) and K=23 (AB, central area; K=22 over full area). The 7 EXOs discovered in the ECDFS may be dusty galaxies at z ∼2-3, or quasars at z>6, or unusually faint galaxies at low redshift. We describe fits to the multi-band SEDs and compare to EXOs found in other deep X-ray surveys.
- Publication:
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American Astronomical Society Meeting Abstracts
- Pub Date:
- December 2005
- Bibcode:
- 2005AAS...207.8021U