Program: GN-2011A-Q-105

We request poor weather time to continue and expand our search for bright objects with featureless infrared spectra on sightlines to the Galactic center (GC). Such objects are needed in order to more thoroughly study the interstellar environment toward and within the GC. Our previous research has used high resolution spectroscopy of H3+ and CO toward known sources in the central few tens of parsecs of the Galaxy to identify a previously unknown but apparently extensive component of warm and diffuse interstellar gas. Evidence to date suggests that this component pervades the central molecular zone (CMZ), which extends ~170 pc from the center, but it is necessary to identify additional smooth-spectrum sources further from the center to use as probes to determine its true extent. We have already identified some candidate sources based on 2MASS and GLIMPSE photometry and have already obtained several striking high-resolution spectra, both within and near the border of the CMZ. The requested time would allow us to survey 65 candidate smooth-spectrum objects from our new list and an additional 55 candidates at somewhat higher galactic latitude, and likely will produce a host of new interstellar sightlines that can be investigated using high-resolution IR spectroscopy.