  "Green fuzzies" or "extended green objects" were discovered in the recent
Spitzer GLIMPSE survey data. These extended sources have enhanced emission in
the 4.5um IRAC channel images (which are generally assigned to be green when
making 3-color RGB images from Spitzer data). Green fuzzies are frequently
found in the vicinities of massive young stellar objects, and it has been
established that they are in some cases associated with outflows. Nevertheless,
the spectral carrier(s) of this enhanced emission is still uncertain. Although
it has been suggested that Br Alpha, H2, [Fe II], and/or broad CO emission may
be contributing to and enhancing the 4.5um flux from these objects, to date
there have been no direct observations of the 4-5um spectra of these objects.
We report here on the first direct spectroscopic identification of the origin
of the green fuzzy emission. We obtained spatially resolved L and M band
spectra for two green fuzzy sources using NIRI on the Gemini North telescope.
In the case of one source, G19.88-0.53, we detect three individual knots of
green fuzzy emission around the source. The knots exhibit a pure molecular
hydrogen line emission spectrum, with the 4.695um v=0-0 S(9) line dominating
the emission in the 4-5um wavelength range, and no detected continuum
component. Our data for G19.88-0.53 prove that green fuzzy emission can be due
primarily to emission lines of molecular hydrogen within the bandpass of the
IRAC 4.5um channel. However, the other target observed, G49.27-0.34, does not
exhibit any line emission and appears to be an embedded massive young stellar
object with a cometary UC HII region. We suggest that the effects of extinction
in the 3-8um wavelength range and an exaggeration in the color stretch of the
4.5um filter in IRAC RGB images could lead to embedded sources such as this one
falsely appearing "green".
