Outflows and luminous YSOs: A new perspective on the G192.16 massive bipolar outflow

We have obtained new observations of the massive molecular outflow in G192. 16-3.82 in CO(J = 1-0) line and 3 mm continuum using the Owens Valley Radio Observatory millimeter-wave array. We have also imaged the outflow in the near-infrared J, H, and K bands and 2.12 mu m H-2 at Lowell Observatory and in the K-s band at the Apache Point Observatory. A large-field Palomar ima ge shows that the outflow structure may extend more than 4 pc from the youn g stellar object (YSO), making it one of the largest known Galactic outflow s. There is approximately 80 M-. of molecular material in the high-velocity flow, and the mass flow rate is similar to 5 x 10(-4) M-. yr(-1). The flow appears to be driven by an early-B star that is surrounded by approximatel y 17 M-. of material. A biconical infrared reflection nebula is centered ne ar the millimeter continuum peak, and shock-excited H-2 emission is detecte d at the brightest peak in the K-band reflection nebula. H-2 emission is al so detected just beyond the highest velocity gas in the blueshifted CO outf low. The slope of the mass spectrum is approximately -2 at velocities below 15 km s(-1) and decreases to as low as -8 at higher velocities. This is si gnificantly steeper than in low-mass outflows, suggesting that the powering mechanism is less efficient at accelerating material in the flow. Alternat ively, the outflow may have built up a substantial reservoir of low-velocit y gas that steepens the mass spectrum. The observation of a wide outflow op ening angle (similar to 60 degrees) and limb-brightened shell surrounding t he high-velocity gas, together with shock-excited H-2 emission and large bo w shocks that extend up to 4 pc from the YSO, are consistent with the prese nce of both a poorly collimated disk-wind and a jet.