title: Resolved images of a protostellar outflow driven by an extended disk wind.
abstract: Young stars are associated with prominent outflows of molecular gas. The ejection of gas is believed to remove angular momentum from the protostellar system, permitting young stars to grow by the accretion of material from the protostellar disk. The underlying mechanism for outflow ejection is not yet understood, but is believed to be closely linked to the protostellar disk. Various models have been proposed to explain the outflows, differing mainly in the region where acceleration of material takes place: close to the protostar itself ('X-wind', or stellar wind), in a larger region throughout the protostellar disk (disk wind), or at the interface between the two. Outflow launching regions have so far been probed only by indirect extrapolation because of observational limits. Here we report resolved images of carbon monoxide towards the outflow associated with the TMC1A protostellar system. These data show that gas is ejected from a region extending up to a radial distance of 25 astronomical units from the central protostar, and that angular momentum is removed from an extended region of the disk. This demonstrates that the outflowing gas is launched by an extended disk wind from a Keplerian disk.
authors.affiliation: Centre for Star and Planet Formation, Niels Bohr Institute &Natural History Museum of Denmark, University of Copenhagen, Øster Voldgade 5-7, 1350 Copenhagen K, Denmark.|Department of Earth and Space Sciences, Chalmers University of Technology, Onsala Space Observatory, 43992 Onsala, Sweden.
authors.forename: Per
authors.initials: P
authors.lastname: Bjerkeli
authors.affiliation: Centre for Star and Planet Formation, Niels Bohr Institute &Natural History Museum of Denmark, University of Copenhagen, Øster Voldgade 5-7, 1350 Copenhagen K, Denmark.|ASTRON, the Netherlands Institute for Radio Astronomy, Postbus 2, 7990 AA Dwingeloo, The Netherlands.
authors.forename: Matthijs H D
authors.initials: MH
authors.lastname: van der Wiel
authors.affiliation: Center for Astronomy, Institute of Theoretical Astrophysics, Heidelberg University, Albert-Ueberle-Straße 2, 69120 Heidelberg, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Harsono
authors.affiliation: Centre for Star and Planet Formation, Niels Bohr Institute &Natural History Museum of Denmark, University of Copenhagen, Øster Voldgade 5-7, 1350 Copenhagen K, Denmark.
authors.forename: Jon P
authors.initials: JP
authors.lastname: Ramsey
authors.affiliation: Centre for Star and Planet Formation, Niels Bohr Institute &Natural History Museum of Denmark, University of Copenhagen, Øster Voldgade 5-7, 1350 Copenhagen K, Denmark.
authors.forename: Jes K
authors.initials: JK
authors.lastname: Jørgensen