Three-dimensional Shock Structure of Orion KL Outflow with IGRINS

Abstract

We report a study of the three-dimensional (3D) outflow structure of a 15$\arcsec$ $\times$ 13$\arcsec$ area around H${}_2$ peak 1 in Orion KL with slit-scan observations (13 slits) using the Immersion Grating Infrared Spectrograph. The datacubes, with high velocity-resolution ($\sim$ 7.5 {\kms}) provide high contrast imaging within ultra-narrow bands, and enable the detection of the main stream of the previously reported H${}_2$ outflow fingers. We identified 31 distinct fingers in H${}_2$ 1$-$0 S(1) $\lambda$2.122 $\micron$ emission. The line profile at each finger shows multiple-velocity peaks with a strong low-velocity component around the systemic velocity at ${\VLSR}$ = $+$8 {\kms} and high velocity emission ($|$${\VLSR}$$|$ = 45$-$135 {\kms}) indicating a typical bow-shock. The observed radial velocity gradients of $\sim$ 4 {\kms} arcsec${}^{-1}$ agree well with the velocities inferred from large-scale proper motions, where the projected motion is proportional to distance from a common origin. We construct a conceptual 3D map of the fingers with the estimated inclination angles of 57$°$$-$74$°$. The extinction difference ($\Delta$$A_{\mathrm{v}}$ $>$ 10 mag) between blueshifted and redshifted fingers indicates high internal extinction. The extinction, the overall angular spread and scale of the flow argue for an ambient medium with very high density (10${}^5$$-$10${}^6$ cm${}^{-3}$), consistent with molecular line observations of the OMC core. The radial velocity gradients and the 3D distributions of the fingers together support the hypothesis of simultaneous, radial explosion of the Orion KL outflow.

arXiv comment32 pages, 12 figure, 2 tables, Accepted for publication in the Astrophysical Journal

References in corpus (24)

• Interstellar Dust Grains
• The distance to the Orion Nebula
• The Luminosity & Mass Function of the Trapezium Cluster: From B stars to the Deuterium Burning Limit
• The Birth of High Mass Stars: Accretion and/or Mergers?
• A Feature Movie of SiO Emission 20-100 AU from the Massive Young Stellar Object Orion Source I
• Molecular Cloud Structure in the Magellanic Clouds: Effect of Metallicity
• Explosive Outflows Powered by the Decay of Non-Hierarchical Multiple Systems of Massive Stars: Orion BN/KL
• Monitoring the Large Proper Motions of Radio Sources in the Orion BN/KL Region
• Jet/cloud collision, 3D gasdynamic simulations of HH 110
• Dynamical decay of a massive multiple system in Orion KL?
• Tracing the Bipolar Outflow from Orion Source I
• The Becklin-Neugebauer Object as a Runaway B Star, Ejected 4000 years ago from the theta^1C system
• Subaru IR Echelle Spectroscopy of Herbig-Haro Driving Sources I. H_2 and [Fe II] Emission
• Deuterated methanol in Orion BN/KL
• Herschel Far-Infrared Spectral-mapping of Orion BN/KL Outflows: Spatial distribution of excited CO, H2O, OH, O and C+ in shocked gas
• The Orion Fingers: Near-IR Adaptive Optics Imaging of an Explosive Protostellar Outflow
• OH maser disc and outflow in the Orion-BN/KL region
• Shocked H2 and Fe+ Dynamics in the Orion Bullets
• Gravitational Slingshot of Young Massive Stars in Orion
• The extinction map of the OMC-1 molecular cloud behind the Orion Nebula
• A study of dynamical processes in the Orion KL region using ALMA-- Probing molecular outflow and inflow
• The near-infrared excitation of the HH211 protostellar outflow
• The Orion fingers: Near-IR spectral imaging of an explosive outflow
• IGRINS Near-IR High-Resolution Spectroscopy of Multiple Jets around LkH$\alpha$ 234

Cited by in corpus (8)

• The full infrared spectrum of molecular hydrogen
• Excitation of Molecular Hydrogen in the Orion Bar Photodissociation Region From a Deep Near-Infrared IGRINS Spectrum
• Fluorescent H_2 Emission Lines from the Reflection Nebula NGC 7023 Observed with IGRINS
• The Orion fingers: H${}_2$ temperatures and excitation in an explosive outflow
• 10 Years of Archival High-Resolution NIR Spectra: The Raw and Reduced IGRINS Spectral Archive (RRISA)
• High-resolution near-IR Spectral mapping with H${}_2$ and [Fe II] lines of Multiple Outflows around LkH$\alpha$ 234
• Modelling the CO streamers in the explosive ejection of Orion BN/KL region
• High-resolution Near-infrared Spectroscopy of Diffuse Sources around MWC 1080