A new CO bipolar flow and dense disk system associated with the infrared reflection nebula GGD 27 IRS

Abstract

Observations of the CO J = 1-0 and CS J = 2-1, 1-0 lines and 1.1 mm continuum emissions around an infrared reflection nebula GGD 27 IRS are presented. These observations revealed that this source is a prototypical molecular bipolar flow which shows shell structure and which is associated with a dense disk. The CO bipolar flow spatially coincides with the infrared reflection nebula, suggesting that the near-infrared light is scattered by the dust whose distribution is conducted by the flow. A spatial coincidence of the expected cavity of the molecular flow with the ionized gas is also noticed, which supports a stellar wind-driven model of the outflow. The density and the mass of the disk are deduced to be 1 x 10 to the 5th/cu cm and 120 solar masses, respectively, from an LVG model calculated for the two transitions of the CS molecule, and greater than 1.2 x 10 to the 5th/cu cm and 400 solar masses from the optical thickness of the cold dust at 1.1 mm.