Gas velocity structure of the Orion A Integral Shaped Filament

Abstract

We present analysis of the gas kinematics of the Integral Shaped Filament (ISF) in Orion~A using four different molecular lines, ${}^{12}$CO (1-0), ${}^{13}$CO (1-0), NH${}_3$ (1,1), and N${}_2$H${}^{+}$ (1-0). We describe our method to visualize the position-velocity (PV) structure using the intensity-weighted line velocity centroid, which enables us to identify structures that were previously muddled or invisible. We observe a north to south velocity gradient in all tracers that terminates in a velocity peak near the center of the Orion Nebula Cluster (ONC), consistent with the previously reported "wave-like" properties of the ISF. We extract the velocity dispersion profiles and compare the non-thermal line widths to the gas gravitational potential. We find supersonic Mach number profiles, yet the line widths are consistent with the gas being deeply gravitationally bound. We report the presence of two ${}^{12}$CO velocity components along the northern half of the ISF; if interpreted as circular rotation, the angular velocity is $\omega =1.4{\mathrm{Myr}}^{-1}$. On small scales we report the detection of N${}_2$H${}^{+}$ and NH${}_3$ "twisting and turning" structures, with short associated timescales that give the impression of a torsional wave. Neither the nature of these structures nor their relation to the larger scale wave is presently understood.

13 pages, 8 figures. Accepted for publication in Monthly Notices of the Royal Astronomical Society Main Journal

References in corpus (9)

• The Critical Density and the Effective Excitation Density of Commonly Observed Molecular Dense Gas Tracers
• A Large Catalog of Accurate Distances to Molecular Clouds from PS1 Photometry
• The JCMT BISTRO Survey: The magnetic field strength in the Orion A filament
• Revealing the physical properties of molecular gas in Orion with a large scale survey in J=2-1 lines of 12CO, 13CO and C18O
• Evolution of column density distributions within Orion~A
• The ALMA View of the OMC1 Explosion in Orion
• Large-scale periodic velocity oscillation in the filamentary cloud G350.54+0.69
• Gaia Stellar Kinematics in the Head of the Orion A Cloud: Runaway Stellar Groups and Gravitational Infall
• The CARMA-NRO Orion Survey: Core Emergence and Kinematics in the Orion A Cloud

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