Multicomponent Kinematics in a Massive Filamentary Infrared Dark Cloud

Journal
Date Issued
2019
Author(s)
Sokolov, Vlas
•
Wang, Ke
•
Pineda, Jaime E.
•
Caselli, Paola
•
Henshaw, Jonathan D.
•
Barnes, Ashley T.
•
Tan, Jonathan C.
•
•
Jiménez-Serra, Izaskun
DOI
Abstract
To probe the initial conditions for high-mass star and cluster formation, we investigate the properties of dense filaments within the infrared dark cloud (IRDC) G035.39-00.33 (G035.39) in a combined Very Large Array and Green Bank Telescope mosaic tracing the NH3 (1, 1) and (2, 2) emission down to 0.08 pc scales. Using agglomerative hierarchical clustering on multiple line-of-sight velocity component fitting results, we identify seven extended velocity-coherent components in our data, likely representing spatially coherent physical structures, some exhibiting complex gas motions. The velocity gradient magnitude distribution peaks at its mode of 0.35 and has a long tail extending into higher values of 1.5-2 , and it is generally consistent with those found toward the same cloud in other molecular tracers and with the values found toward nearby low-mass dense cloud cores at the same scales. Contrary to observational and theoretical expectations, we find the nonthermal ammonia line widths to be systematically narrower (by about 20%) than those of N2H+ (1-0) line transition observed with similar resolution. If the observed ordered velocity gradients represent the core envelope solid-body rotation, we estimate the specific angular momentum to be about 2 × 1021 cm2 s-1, similar to the low-mass star-forming cores. Together with the previous finding of subsonic motions in G035.39, our results demonstrate high levels of similarity between kinematics of a high-mass star-forming IRDC and the low-mass star formation regime.
Volume
872
Issue
1
Start page
30
Uri
Url
Issn Identifier
0004-637X
Ads BibCode
2019ApJ...872...30S
Rights
open.access
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