title: The winds from HL Tau.
abstract: Outflowing motions, whether a wind launched from the disc, a jet launched from the protostar, or the entrained molecular outflow, appear to be a ubiquitous feature of star formation. These outwards motions have a number of root causes, and how they manifest is intricately linked to their environment as well as the process of star formation itself. Using the Atacama Large Millimeter/submillimeter Array (ALMA) Science Verification data of HL Tau, we investigate the high-velocity molecular gas being removed from the system as a result of the star formation process. We aim to place these motions in context with the optically detected jet, and the disc. With these high-resolution (∼1 arcsec) ALMA observations of CO (J=1-0), we quantify the outwards motions of the molecular gas. We find evidence for a bipolar outwards flow, with an opening angle, as measured in the redshifted lobe, starting off at 90°, and narrowing to 60° further from the disc, likely because of magnetic collimation. Its outwards velocity, corrected for inclination angle is of the order of 2.4 km s-1.
authors: UK Astronomy Technology Centre, Royal Observatory Edinburgh, Blackford Hill, Edinburgh EH9 3HJ, UK.
authors: P D
authors: PD
authors: Klaassen
authors: Leiden Observatory, Leiden University, PO Box 9513, NL-2300 RA Leiden, the Netherlands; Max-Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg, Germany.
authors: J C
authors: JC
authors: Mottram
authors: Leiden Observatory, Leiden University, PO Box 9513, NL-2300 RA Leiden, the Netherlands.
authors: L T
authors: LT
authors: Maud
authors: Institute of Astronomy, Madingley Road, Cambridge CB3 OHA, UK.
authors: A
authors: A
authors: Juhasz
keywords: ISM: jets and outflows; stars: formation; stars: winds, outflows; submillimetre: ISM; techniques: interferometric