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We briefy describe the results of a K-band spectroscopic survey of over 500highly reddened point-like objects on sightlines toward the Central MolecularZone (CMZ) of the Galaxy. The goal was to find stars with featureless or nearlyfeatureless spectra suitable for near- and mid-infrared absorption spectroscopyof the Galactic center's interstellar gas on sightlines spread across the CMZ.Until recently only a few such stars have been known outside of very localizedsightlines in the vicinity of the Quintuplet and Central clusters. We have usedSpitzer Space Telescope (GLIMPSE) and 2MASS photometry to select promisingcandidates, and over the last ten years have been acquiring low-resolutionK-band spectra of them. As expected, the vast majority are cool and/or highlyreddened red giants with complex photospheric spectra unsuitable for measuringfaint interstellar lines. Approximately ten percent of them, whose observationsare reported here, have featureless or nearly featureless spectra. Although notevenly distributed in Galactic longitude, these stars are scattered across theCMZ. Many of them are luminous stars that are deeply embedded in warm dustcocoons, and have K-band continua rising steeply to longer wavelengths. Asignificant fraction of them are hot stars of a variety of spectral types,including at least five newly discovered Wolf-Rayet stars. All of them shouldbe suitable for spectroscopy of interstellar absorption lines at infraredwavelengths greater than 3 microns and many are also suitable at shorterwavelengths.

Background Infrared Sources for Studying the Galactic Center's Interstellar Gas