2016ApJ...829..106O

We present the results of near-infrared (2.5-5.4 µm) long-slit spectroscopy of the extended green object (EGO) G318.05+0.09 with AKARI. Two distinct sources are found in the slit. The brighter source has strong red continuum emission with H₂O ice, CO₂ ice, and CO gas and ice absorption features at 3.0, 4.25 µm, 4.67 µm, respectively, while the other greenish object shows peculiar emission that has double peaks at around 4.5 and 4.7 µm. The former source is located close to the ultra compact H ii region IRAS 14498-5856 and is identified as an embedded massive young stellar object (YSO). The spectrum of the latter source can be interpreted by blueshifted (-3000 ∼ -6000 km/s) optically thin emission of the fundamental ro-vibrational transitions (v=1–0) of CO molecules with temperatures of 12000-3700 K without noticeable H₂ and H i emission. We discuss the nature of this source in terms of outflow associated with the young stellar object and supernova ejecta associated with a supernova remnant.