BIPOLAR MOLECULAR OUTFLOWS AND HOT CORES IN GLIMPSE EXTENDED GREEN OBJECTS (EGOs)

We present high angular resolution Submillimeter Array and Combined Array for Research in Millimeter-wave Astronomy observations of two GLIMPSE Extended Green Objects (EGOs)-massive young stellar object (MYSO) outflow candidates identified based on their extended 4.5 um emission in Spitzer images. The millimeter observations reveal bipolar molecular outflows, traced by high-velocity 12CO(2-1) and HCO+(1-0) emission, coincident with the 4.5 um lobes in both sources. SiO(2-1) emission confirms that the extended 4.5 um emission traces active outflows. A single dominant outflow is identified in each EGO, with tentative evidence for multiple flows in one source (G11.92-0.61). The outflow driving sources are compact millimeter continuum cores, which exhibit hot core spectral line emission and are associated with 6.7 GHz Class II CH3OH masers. G11.92-0.61 is associated with at least three compact cores: the outflow driving source, and two cores that are largely devoid of line emission. In contrast, G19.01-0.03 appears as a single MYSO. The difference in multiplicity, the comparative weakness of its hot core emission, and the dominance of its extended envelope of molecular gas all suggest that G19.01-0.03 may be in an earlier evolutionary stage than G11.92-0.61. Modeling of the G19.01-0.03 spectral energy distribution suggests that a central (proto) star (M~10 M_sun) has formed in the compact millimeter core (M_gas ~ 12-16 M_sun), and that accretion is ongoing at a rate of ~10^-3 M_sun/year. Our observations confirm that these EGOs are young MYSOs driving massive bipolar molecular outflows and demonstrate that considerable chemical and evolutionary diversity are present within the EGO sample.