We report a moderate-depth ( 70 ksec ) , contiguous 0.7 deg ^ { 2 } , Chandra survey , in the Lockman Hole Field of the Spitzer /SWIRE Legacy Survey coincident with a completed , ultra-deep VLA survey with deep optical and near-infrared ( NIR ) imaging in-hand .
The primary motivation is to distinguish starburst galaxies and Active Galactic Nuclei , including the significant , highly obscured ( log { N _ { H } } > 23 ) subset . Chandra has detected 775 X-ray sources to a limiting broad band ( 0.3-8 keV ) flux \sim 4 \times 10 ^ { -16 } erg cm ^ { -2 } s ^ { -1 } .
We present the X-ray catalog , fluxes , hardness ratios and multi-wavelength fluxes .
The log N vs. log S agrees with those of previous surveys covering similar flux ranges .
The Chandra and Spitzer flux limits are well matched : 771 ( 99 % ) of the X-ray sources have IR ( infared ) or optical counterparts , and 333 have MIPS 24 \mu m detections .
There are 4 optical-only X-ray sources and 4 with no visible optical/IR counterpart .
The very deep ( \sim 2.7 \mu Jy rms ) VLA data yields 251 ( > 4 \sigma ) radio counterparts , 44 % of the X-ray sources in the field .
We confirm that the tendency for lower X-ray flux sources to be harder is primarily due to absorption .
As expected , there is no correlation between observed IR and X-ray flux .
Optically bright , Type 1 and red AGN lie in distinct regions of the IR vs X-ray flux plots , demonstrating the wide range of SEDs in this sample and providing the potential for classification/source selection .
Many optically-bright sources , which lie outside the AGN region in the optical vs X-ray plots ( f _ { r } / f _ { x } > 10 ) , lie inside the region predicted for red AGN in IR vs X-ray plots consistent with the presence of an active nucleus .
More than 40 % of the X-ray sources in the VLA field are radio-loud using the classical definition , R _ { L } .
The majority of these are red and relatively faint in the optical so that the use of R _ { L } to select those AGN with the strongest radio emission becomes questionable .
Using the 24 \mu m to radio flux ratio ( q _ { 24 } ) instead results in 13 of the 147 AGN with sufficient data being classified as radio-loud , in good agreement with the \sim 10 % expected for broad-lined AGN based on optical surveys .
We conclude that q _ { 24 } is a more reliable indicator of radio-loudness .
Use of R _ { L } should be confined to optically-selected , Type 1 AGN .