The Cosmos Active Galactic Nucleus Spectroscopic Survey. I.XMM-NEWTONCOUNTERPARTS

We present optical spectroscopy for an X-ray and optical flux-limited of 677 XMM-Newton selected targets covering the 2 deg2 Evolution Survey field, with a yield of 485 high-confidence. The majority of the spectra were obtained over three seasons (2005-2007) with the Inamori Magellan Areal Camera and Spectrograph on the Magellan (Baade) telescope. We also include in the previously published Sloan Digital Sky Survey spectra and observations with MMT/Hectospec. We detail the observations classification analyses. The survey is 90% complete to flux limits f 0. 5-10 keV > 8 × 10-16 erg-2 s-1 and i + AB + 0. 5-10 > 3 × 1042 erg s-1) to z <1, of both optically obscured and unobscured types. We find significant evidence that the obscured-to-unobscured AGN at z < 1 increases with redshift and decreases with luminosity. on observations with the NASA/ESA Hubble Space Telescope, obtained the Space Telescope Science Institute, which is operated by AURA. , under NASA contract NAS 5-26555; the XMM-Newton, an ESA science with instruments and contributions directly funded by ESA Member and NASA; the Magellan Telescope, which is operated by the Observatories; and the MMT, operated by the MMT Observatory, a venture of the Smithsonian Institution and the University of.