1. Optical Spectroscopy of Serendipitous X-ray Sources Ezequiel Treister Ezequiel Treister (U. de Chile/Yale) E. Gawiser C.M.Urry, P. Coppi (Yale) F. Castander (IEEC-Barcelona) T. Maccarone (Amsterdam)

2. The AGN Unified Model blazars, Type 1 Sy/QSO broad lines Urry & Padovani, 1995 radio galaxies, Type 2 Sy/QSO narrow lines

3. Population Synthesis Models Gilli et al. 1999 Gilli et al. 2001 Giacconi et al. 1979 Setti & Woltjer 1989 Madau et al. 1994 Comastri et al. 1995

4. Hasinger 2002 Gilli et al. population synthesis predictions Redshift Distribution

5. Hidden Population of Obscured AGN at high-z  Not Found in UV/Optical Surveys.  Multiwavelength Surveys needed:  Hard X-rays (Chandra)  Far-IR (Spitzer)  Optical Spectroscopy (VLT-Magellan)

6. Calán Yale Deep Extragalactic Research The CYDER Survey

7. CYDER Survey Optical follow up of X-ray sources in moderately deep archived Chandra fields (>50 ks). 5 fields spread in RA, no large cluster on the field. Deep V,I images from CTIO 4m. Optical Spectroscopy from Magellan (LDSS-2) and VLT (FORS2). All sources targeted for spectroscopy, independent of optical magnitude.

8. V-magnitude Distribution All X-ray Sources Targeted for Spectroscopy Identified Sources

9. Redshift Distribution All X-ray Sources AGN-Dominated Sources Unobscured AGN

10. Results Source Composition similar to Deep X-ray Surveys.

11. Populations ObjectCYDERChaMPCDF-NCDF-S Unobs. AGN47.2%52.1%12.4%35.0% Obs. AGN35.8%23.9%39.4%42.7% Galaxies10.4%14.1%43.3%17.8% Stars6.6%9.9%4.9%4.5% Total106125284168

12. Results Source Composition similar to Deep X-ray Surveys. Obscured AGN have redder colors and are consistent with being host galaxy dominated in optical light. with being host galaxy dominated in optical light.

13. V-mag versus Redshift

14. V-I versus Redshift

15. Results Source Composition similar to Deep X-ray Surveys. Obscured AGN have redder colors and are consistent with being host galaxy dominated in optical light. Correlation between F x /F opt versus X-ray luminosity for obscured AGN. obscured AGN.

16. F x /F opt versus X-ray Luminosity

17. F X /F opt Ratio Fiore et al, 2003

18. Results Source Composition similar to Deep X-ray Surveys. Obscured AGN have redder colors and are consistent with being host galaxy dominated in optical light. Correlation between F x /F opt versus X-ray luminosity for obscured AGN. Correlation between obscured-to-total AGN ratio and hard X-ray luminosity. hard X-ray luminosity.

19. Obscured to Total AGN Ratio Fraction of Obscured AGN Intrinsic Hard X-ray Luminosity [erg s -1 ]

20. Conclusions Source Composition similar to Deep X-ray Surveys. Only depends on spectroscopic coverage Obscured AGN have redder colors and are consistent with being host galaxy dominated in optical light. Red Colors from obscuration? Needs more study Correlation between F x /F opt versus X-ray luminosity for obscured AGN. Consequence of obscured AGN being host-galaxy dominated Correlation between obscured-to-total AGN ratio and hard X-ray luminosity. Can be a selection effect

21. Multiwavelength Survey by Yale-Chile (MUSYC) Jose Maza Eric Gawiser Meg Urry Paulina Lira Pieter van Dokkum Maria Teresa Ruiz Bill van Altena Rene Mendez Leopoldo Infante David Herrera Sebastian Lopez Gaspar Galaz Francisco Castander Paolo Coppi Sukyoung Yi Charles Liu Marijn Franx Ezequiel Treister Ryan Quadri Leonor Huerta

22. First MUSYC Spectra BVR Image Vmag~22.8 z=2.65

23. First MUSYC Spectra BVR Image Vmag~22.5 z=2.00