Program: GN-2010A-Q-92

We request poor weather time to expand our search for bright objects with featureless infrared spectra in the line of sight to the Galactic center (GC). Such objects are needed in order to more thoroughly study the interstellar environment toward and within the center. 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 the gas' true extent. We have started identifying such sources based on 2MASS and GLIMPSE photometry and have already obtained some striking results both within and near the border of the CMZ. The poor weather time requested here would allow us to survey 120 candidate smooth-spectrum objects and likely will produce a host of new sightlines that can be investigated using high-resolution IR spectroscopy.