Deep X-ray surveys with the Chandra Observatory are providing a remarkable window on the high-energy universe.  In particular, the Chandra Deep Field - South survey and its extended area coverage are providing new insights into the growth of obscured supermassive black holes (i.e., Active Galactic Nuclei-AGN), the hot intragroup medium of galaxy groups, and star-forming galaxies.   

Wavelength (Å)

We have been undertaking an intensive multi-wavelength campaign (Silverman et al. 2010) to fully characterize the nature of these faint X-ray sources.  We have utilized 8-10m class optical telescopes (Very Large Telescope-VLT, Keck) to identify the source of these X-rays and determine their distance (i.e., redshift).  For example, we show optical spectra from the VLT of two different AGNs.  The first is a typical, luminous AGN with broad emission lines emitted from gas in the vicinity of the supermassive black hole.  Whereas, the second case is optically-underluminous such that only a hint of an emission-line (i.e., Lyα), possibly powered by the AGN, is evident (Click here for further details and access to the data products).