First Spectroscopic Identification of Massive Young Stellar Objects in
  the Galactic Center
  We report the detection of several molecular gas-phase and ice absorption
features in three photometrically-selected young stellar object (YSO)
candidates in the central 280 pc of the Milky Way. Our spectra, obtained with
the Infrared Spectrograph (IRS) onboard the Spitzer Space Telescope, reveal
gas-phase absorption from CO2 (15.0um), C2H2 (13.7um) and HCN (14.0um). We
attribute this absorption to warm, dense gas in massive YSOs. We also detect
strong and broad 15um CO2 ice absorption features, with a remarkable
double-peaked structure. The prominent long-wavelength peak is due to
CH3OH-rich ice grains, and is similar to those found in other known massive
YSOs. Our IRS observations demonstrate the youth of these objects, and provide
the first spectroscopic identification of massive YSOs in the Galactic Center.
