We present the SEDs of a hard X-ray selected sample containing 136 sources with F 2Y10 keV > 10 À14 erg cm À2 s À1 ; 132 are AGNs. The sources are detected in a 1 deg 2 area of the XMM-Newton Medium Deep Survey where optical data from the VVDS and CFHTLS and infrared data from the SWIRE survey are available. Based on a SED fitting technique we derive photometric redshifts with (1 þ z) ¼ 0:11 and 6% of outliers and identify AGN signatures in 83% of the objects. This fraction is higher than derived when a spectroscopic classification is available. The remaining 17 þ9 À6 % of AGNs show star-forming galaxy SEDs (SF class). The sources with AGN signatures are divided in two classes, AGN1 (33 þ6 À1 %) and AGN2 (50 þ6 À11 %). The AGN1 and AGN2 classes include sources whose SEDs are fitted by type 1 and type 2 AGN templates, respectively. On average, AGN1s show soft X-ray spectra, consistent with being unabsorbed, while AGN2s and SFs show hard X-ray spectra, consistent with being absorbed. The analysis of the average SEDs as a function of X-ray luminosity shows a reddening of the infrared SEDs, consistent with a decreasing contribution from the host galaxy at higher luminosities. The AGNs in the SF classes are likely obscured in the mid-infrared, as suggested by their low L 3Y20 m /L corr 0:5Y10 keV ratios. We confirm the previously found correlation for AGNs between the radio luminosity and the X-ray and the mid-infrared luminosities. The X-rayYradio correlation can be used to identify heavily absorbed AGNs. However, the estimated radio fluxes for the missing AGN population responsible for the bulk of the background at E > 10 keV are too faint to be detected even in the deepest current radio surveys.

Far ultraviolet to far infrared images of the nearby galaxy NGC 5194 (M51a), from a combination of space-based (Spitzer, GALEX, and Hubble Space Tele-1 Based on observations obtained with the Spitzer Space Telescope and with GALEX.

We present the first results from the Australia Telescope Large Area Survey, which consists of deep radio observations of a 3.7 deg 2 field surrounding the Chandra Deep Field-South, largely coincident with the infrared Spitzer Wide-Area Infrared Extragalactic (SWIRE) Survey. We also list cross-identifications to infrared and optical photometry data from SWIRE, and ground-based optical spectroscopy. A total of 784 radio components are identified, corresponding to 726 distinct radio sources, nearly all of which are identified with SWIRE sources. Of the radio sources with measured redshifts, most lie in the redshift range 0.5-2 and include both star-forming galaxies and active galactic nuclei. We identify a rare population of infrared-faint radio sources that are bright at radio wavelengths but are not seen in the available optical, infrared, or X-ray data. Such rare classes of sources can only be discovered in wide, deep surveys such as this.

Using the large multiwavelength data set in the Chandra/SWIRE Survey (0.6 deg 2 in the Lockman Hole), we show evidence for the existence of highly obscured (Compton-thick) AGNs, estimate a lower limit to their surface density, and characterize their multiwavelength properties. Two independent selection methods based on the X-ray and infrared spectral properties are presented. The two selected samples contain (1) five X-ray sources with hard X-ray spectra and column densities k10 24 cm À2 and (2) 120 infrared sources with red and AGN-dominated infrared SEDs. We estimate a surface density of at least 25 Compton-thick AGNs deg À2 detected in the infrared in the Chandra/ SWIRE field, of which $40% show distinct AGN signatures in their optical/near-infrared SEDs, the remaining being dominated by the host galaxy emission. Only $33% of all Compton-thick AGNs are detected in the X-rays at our depth [F(0:3 8 keV) > 10 À15 ergs cm À2 s À1 ]. We report the discovery of two sources in our sample of Comptonthick AGNs, SWIRE J104409.95+585224.8 (z ¼ 2:54) and SWIRE J104406.30+583954.1 (z ¼ 2:43), which are the most luminous Compton-thick AGNs at high z currently known. The properties of these two sources are discussed in detail with an analysis of their spectra, SEDs, luminosities, and black hole masses.

The SIRTF Wide-area InfraRed Extragalactic survey (SWIRE), the largest SIRTF Legacy program, is a wide-area, imaging survey to trace the evolution of dusty, starforming galaxies, evolved stellar populations, and AGN as a function of environment, from redshifts z∼3 to the current epoch. SWIRE will survey 7 high-latitude fields, totaling 60-65 sq. deg. in all 7 SIRTF bands: IRAC 3.6, 4.5, 5.6, 8µm and MIPS 24, 70, 160µm. Extensive modeling suggests that the Legacy Extragalactic Catalog may contain in excess of 2 million IR-selected galaxies, dominated by (1) ∼150,000 luminous infrared galaxies (LIRGs: L F IR > 10 11 L ⊙) detected by MIPS (and significantly more detected by IRAC), ∼7,000 of these with z>2; (2) 1 million IRAC-detected early-type galaxies (∼ 2×10 5 with z > 1 and ∼10,000 with z > 2); and (3) ∼ 20,000 classical AGN detected with MIPS, plus significantly more dust-obscured QSO/AGN among the LIRGs. SWIRE will provide an unprecedented view of the evolution of galaxies, structure, and AGN. The key scientific goals of SWIRE are: (1) to determine the evolution of actively star-forming and passively evolving galaxies in order to understand the history of galaxy formation in the context of cosmic structure formation; (2) to determine the evolution of the spatial distribution and clustering of evolved galaxies, starbursts and AGN in the key redshift range, 0.5