AEGIS-X: Deep Chandra Imaging of the Central Groth Strip

September 2015 • 2015ApJS..220...10N

Authors • Nandra, K. • Laird, E. S. • Aird, J. A. • Salvato, M. • Georgakakis, A. • Barro, G. • Perez-Gonzalez, P. G. • Barmby, P. • Chary, R. -R. • Coil, A. • Cooper, M. C. • Davis, M. • Dickinson, M. • Faber, S. M. • Fazio, G. G. • Guhathakurta, P. • Gwyn, S. • Hsu, L. -T. • Huang, J. -S. • Ivison, R. J. • Koo, D. C. • Newman, J. A. • Rangel, C. • Yamada, T. • Willmer, C.

Abstract • We present the results of deep Chandra imaging of the central region of the Extended Groth Strip, the AEGIS-X Deep (AEGIS-XD) survey. When combined with previous Chandra observations of a wider area of the strip, AEGIS-X Wide (AEGIS-XW), these provide data to a nominal exposure depth of 800 ks in the three central ACIS-I fields, a region of approximately 0.29 deg2. This is currently the third deepest X-ray survey in existence; a factor ∼ 2-3 shallower than the Chandra Deep Fields (CDFs), but over an area ∼3 times greater than each CDF. We present a catalog of 937 point sources detected in the deep Chandra observations, along with identifications of our X-ray sources from deep ground-based, Spitzer, GALEX, and Hubble Space Telescope imaging. Using a likelihood ratio analysis, we associate multiband counterparts for 929/937 of our X-ray sources, with an estimated 95% reliability, making the identification completeness approximately 94% in a statistical sense. Reliable spectroscopic redshifts for 353 of our X-ray sources are available predominantly from Keck (DEEP2/3) and MMT Hectospec, so the current spectroscopic completeness is ∼38%. For the remainder of the X-ray sources, we compute photometric redshifts based on multiband photometry in up to 35 bands from the UV to mid-IR. Particular attention is given to the fact that the vast majority the X-ray sources are active galactic nuclei and require hybrid templates. Our photometric redshifts have mean accuracy of σ =0.04 and an outlier fraction of approximately 5%, reaching σ =0.03 with less than 4% outliers in the area covered by CANDELS . The X-ray, multiwavelength photometry, and redshift catalogs are made publicly available.


IPAC Authors

Ranga-Ram Chary

Senior Scientist