Program: GN-2016A-Q-98

We request Band 4 time with GNIRS on Gemini North to extend our survey of red IR sources in the Galactic center, by obtaining K-band spectrocopy of a newly identified set of 28 objects. The spectra will determine if they have featureless infrared spectra on sightlines to the Galactic center and thus are suitable for high resolution spectroscopy of the interstellar gas of the Galaxy's Central Molecular Zone (CMZ). The new objects are listed in the Spitzer GLIMPSE survey and are brigh in its L band, and can be seen in 2MASS K-band images, but either are absent or are very faint in the 2MASS H and J images, and so are not listed in the 2MASS catalogue. Originally we used high-resolution L-band spectroscopy of H3+ and K-band spectroscopy CO toward known sources in the central few tens of parsecs of the Galaxy to identify a previously unknown but apparently extensive component of the interstellar environment there: warm and diffuse gas. By using Gemini N & S in recent semesters and other telescopes in previous semesters to observe candidate sources identified from 2MASS and GLIMPSE photometry, we have already identified several dozen featureless (dust-embedded) stars in the CMZ, but up to 150 pc distant from the very enter, and have obtained striking high-resolution spectra, extending our knowledge of the extent of and physical conditions in the Galactic center's interstellar gas. More such objects are needed in order to more thoroughly map the interstellar gas toward and within the GC.