Program: GN-2010B-SV-151

The deepest observations ever taken in the far-infrared (100-500 microns) have been recently completed by Herschel as a part of the GOODS-Herschel key program. We propose to study a sample of ULIRGs detected at these wavelengths at z~2 in GOODS-N by obtaining near-infrared (rest-frame optical) spectroscopy. We request 4.7 hours on Gemini-North to use GNIRS to obtain continuous spectroscopy in the J, H, and K bands of 2 ULIRGs carefully selected to have spectroscopic redshifts such that all of the key diagnostic emission lines will be observable and unaffected by sky lines. These two targets are bright in the infrared and are expected to have strong emission lines based on their total infrared luminosity and thus give us the best chance of observing all of the standard diagnostic lines. Using standard emission line diagnostic techniques, we will look for signatures of AGN as a function of L_IR, dust temperature, and SED shape and compare the results to those from several other AGN selection methods. This program will allow us to investigate the role of AGN activity at z>2 consistently in a sample not biased by hot- or cold-dust selection for the first time.