An infrared quintuplet near the Galactic center

A compact cluster of five luminous infrared sources has been found in the vicinity of the Galactic center radio arc. All of the sources have large polarizations in the near-infrared and deep silicate absorptions at 10 μm. Strong absorption lines of CO are seen at 4.6 μm toward each source. The observed polarization and spectral features are likely to be interstellar in origin. The temperatures of the sources, based on infrared photometry and corrected for extinction, are in the range 600-900 K. None of the sources show either infrared recombination line emission from atomic hydrogen, lines of molecular hydrogen, or overtone band of CO at 2.3 μm. Because the objects are tightly clustered, all are likely to be very young objects; however, accurate classifications cannot be made at the present time.