The CO 2-0 first overtone rotational-vibrational bandhead for source 268 in M17.

The CO 2-0 first overtone rotational-vibrational bandhead for source 268 in M17. The blue-shifted shoulder of the profile and redshifted peak are characteristic of Keplerian disks. The smooth curve is a model for the emission profile arising from such a disk. The short vertical line marks the vacuum rest wavelength of the bandhead (2.2935 microns), and the inset shows the emission-line profile for a single line in the bandhead (v=2-0, J=51-50). The x-axis of the inset is in km/s and is one Phoenix grating setting in extent. CO emission was originally observed in this object at low spectral resolution by Hanson et al. (1997).