Multi-epoch Sub-arcsecond [Fe II] Spectroimaging of the DG Tau Outflows with NIFS. I. First data epoch

Abstract

Investigating the outflows emanating from young stellar objects (YSOs) on sub-arcsecond scales provides important clues to the nature of the underlying accretion-ejection process occurring near the central protostar. We have investigated the structures and kinematics of the outflows driven by the YSO DG Tauri, using the Near-infrared Integral Field Spectrograph (NIFS) on Gemini North. The blueshifted outflow shows two distinct components in [Fe II] 1.644 micron emission, which are separated using multi-component line fitting. A stationary recollimation shock is observed, in agreement with previous X-ray and FUV observations. The presence of this shock indicates that the innermost streamlines of the high-velocity component are launched at a very small radius, 0.01-0.15 AU, from the central star. The jet accelerates and expands downstream of the recollimation shock; the 'acceleration' is likely a sign of velocity variations in the jet. No evidence of rotation is found, and we compare this non-detection to previous counter-claims. Moving jet knots, likely the result of the jet velocity variations, are observed. One of these knots moves more slowly than previously observed knots, and the knot ejection interval appears to be non-periodic. An intermediate-velocity component surrounds this central jet, and is interpreted as the result of a turbulent mixing layer along the jet boundaries. Such lateral entrainment requires the presence of a magnetic field of strength a few mG or less at hundreds of AU above the disc surface, which is argued to be a reasonable proposition. In H2 1-0 S(1) 2.1218 micron emission, a wide-angle, intermediate-velocity blueshifted outflow is observed. Both outflows are consistent with being launched by a magnetocentrifugal disc wind, although an X-wind origin for the high-velocity jet cannot be ruled out.

arXiv comment28 pages, 19 figures, accepted for publication in MNRAS

References in corpus (56)

• Theory of Star Formation
• Statistics: Handle with Care, Detecting Multiple Model Components with the Likelihood Ratio Test
• Observational Constraints on the Formation and Evolution of Binary Stars
• The Physics of Star Formation
• Which jet launching mechanism(s) in TTauri stars?
• Accretion-powered Stellar Winds as a Solution to the Stellar Angular Momentum Problem
• On the Evolutionary Status of Class I Stars and Herbig-Haro Energy Sources in Taurus-Auriga
• HST/STIS Spectroscopy of the Optical Outflow from DG Tau: Indications for Rotation in the Initial Jet Channel
• HST/STIS spectroscopy of the optical outflow from DG Tau: structure and kinematics on sub-arcsecond scales
• The Structure and Emission of the Accretion Shock in T Tauri Stars II: the Ultraviolet Continuum Emission
• MHD simulations of jet acceleration from Keplerian accretion disks: the effects of disk resistivity
• Rotation of Jets from Young Stars: New Clues from the Hubble Space Telescope Imaging Spectrograph
• Locating the Launching Region of T Tauri Winds: The Case of DG Tau
• Investigating planet formation in circumstellar disks: CARMA observations of RY Tau and DG Tau
• The X-ray afterglow of the Gamma-ray burst of May 8, 1997: spectral variability and possible evidence of an iron line
• Further Indications of Jet Rotation in New Ultraviolet and Optical HST/STIS Spectra
• The Physical Natures of Class I and Flat-Spectrum Protostellar Photospheres: A Near-Infrared Spectroscopic Study
• Spatially Resolved Molecular Hydrogen Emission in the Inner 200AU Environments of Classical T Tauri Stars
• Discovery of a bipolar X-ray jet from the T Tauri star DG Tau
• Predicted rotation signatures in MHD disc winds and comparison to DG Tau observations
• T Tauri Jet Physics Resolved Near The Launching Region with the Hubble Space Telescope
• Spatially resolved observations of warm ionized gas and feedback in local ULIRGs
• The Origins of Fluorescent H2 Emission From T Tauri~Stars
• Observations of T-Tauri Stars using HST-GHRS: I. Far Ultraviolet Emission Lines
• Evidence for an X-Ray Jet in DG Tau A?
• Momentum Transfer by Astrophysical Jets
• Stationary accretion disks launching super fast-magnetosonic MHD jets
• IRAS 05436-0007 and the Emergence of McNeil's Nebula
• X-rays from jet-driving protostars and T Tauri stars
• Gemini GMOS/IFU spectroscopy of NGC 1569 - I: Mapping the properties of a young star cluster and its environment
• Dynamics and Energetics of Turbulent, Magnetized Disk Accretion around Black Holes: a First-Principles Approach to Disk-Corona-Outflow Coupling
• Magnetic Fields in Stellar Jets
• Is there really a Black Hole at the center of NGC 4041? - Constraints from gas kinematics
• Spatially Extended Brackett Gamma Emission in the Environments of Young Stars
• HeI 1.083 micron emission and absorption in DG Tau: line excitation in jet, hot wind, and accretion flow
• The nature of the soft X-ray source in DG Tau
• The kinematic relationship between disk and jet in the DG Tauri system
• Sub-arcsecond [FeII] spectro-imaging of the DG Tau jet: Periodic bubbles and a dusty disk wind?
• Origin of the wide-angle hot H2 in DG Tauri: New insight from SINFONI spectro-imaging
• Bow shocks, Wiggling Jets, and Wide-Angle Winds: A High Resolution Study of the Entrainment Mechanism of the PV Ceph Molecular (CO) Outflow
• V1647 Orionis: Reinvigorated Accretion and the Re-Appearance of McNeil's Nebula
• Entrainment Mechanisms for Outflows in the L1551 Star-Forming Region
• Detection of a warm molecular wind in DG Tauri
• V1647 Orionis: One Year into Quiescence
• Classical T Tauri stars as sources of parsec-scale optical outflows
• X-ray emission from protostellar jet HH 154: the first evidence of a diamond shock?
• Hubble Space Telescope Images of the Subarcsecond Jet in DG Tau
• Jet rotation investigated in the near-ultraviolet with HST/STIS
• Radio continuum emission from knots in the DG Tau jet
• Revealing the fastest component of the DG Tau outflow through X-rays
• The interactions of winds from massive young stellar objects: X-ray emission, dynamics, and cavity evolution
• Proper Motion Studies of Outflows from Classical T Tauri Stars
• HST FUV C IV observations of the hot DG Tauri jet
• VLA Observations of DG Tau's Radio Jet: A highly collimated thermal outflow
• Sub-arcsecond high sensitivity measurements of the DG~Tau jet with e-MERLIN
• Side-entrainment in a jet embedded in a sidewind

Cited by in corpus (19)

• Connection between jets, winds and accretion in T Tauri stars: the X-shooter view
• A Search for Consistent Jet and Disk Rotation Signatures in RY Tau
• ALMA detects a radial disk wind in DG Tau
• Multi-epoch Sub-arcsecond [Fe II] Spectroimaging of the DG Tau Outflows with NIFS. II. On the Nature of the Bipolar Outflow Asymmetry
• Launching the asymmetric bipolar jet of DO Tau
• Centrifugally driven winds from protostellar accretion discs. I - Formulation and initial results
• The small-scale HH34 IRS jet as seen by X-shooter
• Time-Variable Jet Ejections from RW Aur A, RY Tau and DG Tau
• Formation of X-ray emitting stationary shocks in magnetized protostellar jets
• Recollimation boundary layers as X-ray sources in young stellar jets
• The [Ne III] Jet of DG Tau and its Ionization Scenarios
• The G2+G2t complex as a fast and massive outflow?
• On the Nature of the T Tauri Triple System
• Ejection Patterns in the DG Tau Jet Over the Last 40 Years: Insights into Mass Accretion Variability
• Investigating the nature of the extended structure around the Herbig star RCrA using integral field and high-resolution spectroscopy
• Monitoring inner regions in the RY Tau jet
• 3D AMR hydrosimulations of a compact source scenario for the Galactic Centre cloud G2
• Pre main sequence: Accretion & Outflows
• Variability and Jet Activity in the YSO MHO~3252~Y3 in Serpens South