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M. Polletta (UCSD), C.J. Lonsdale (IPAC/Caltech & UCSD), B.J. Wilkes (Harvard/Smithsonian CfA), J.A. Surace (SSC/Caltech), B. Siana, H.E. Smith (UCSD), D.-W. Kim (Harvard/Smithsonian CfA)
The high sensitivity and spatial resolution of the Spitzer Space Telescope and of the Chandra X-ray Observatory provide, for the first time, a laboratory to investigate the properties of large samples of Active Galactic Nuclei (AGN) over large cosmic volumes. The first results from a 0.6 square degrees Spitzer/Chandra survey performed in the Lockman Hole are presented. The Chandra observations combine 9 pointings of 70 ks and the Spitzer data are part of the Spitzer Wide-Area InfraRed Extragalactic (SWIRE) Survey Legacy Project. Unobscured AGN show distinct properties in their observed mid-infrared (mid-IR) spectral energy distributions, however, obscured AGN and a large fraction of X-ray AGN are indistinguishable from normal and starburst galaxies in this wavelength range. We present the 3-24 micron IR detection statistics of over 900 X-ray sources and investigate their X-ray-optical-IR spectral energy distributions. Our results are compared to models for the joint properties of deep IR and X-ray selected AGN samples. The comparison between X-ray and infrared-selected AGN samples provide strong constraints on AGN counts, on the fraction of obscured AGN and their contribution to the Cosmic Infrared and X-ray backgrounds. Support for this work, part of the Spitzer Space Telescope Legacy Science Program, was provided by NASA through an award issued by the Jet Propulsion Laboratory, California Institute of Technology under NASA contract 1407.
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Bulletin of the American Astronomical Society, 36 5
© 2004. The American Astronomical Society.