Vol 21, No 8

Symmetry properties and widths of the filamentary structures in the Orion A giant molecular cloud

Yu-Qing Zheng, Hong-Chi Wang, Yue-Hui Ma, Chong Li


Abstract We identify 225 filaments from an H2 column density map constructed using simultaneous 12CO, 13CO and C18O (J=1–0) observations carried out as a part of the Milky Way Imaging Scroll Painting (MWISP) project.We select 46 long filaments with lengths above 1.2 pc to analyze the filament column density profiles. We divide the selected filaments into 397 segments and calculate the column density profiles for each segment. The symmetries of the profiles are investigated. The proportion of intrinsically asymmetrical segments is 65.3%, and that of intrinsically symmetrical ones is 21.4%. The typical full width at half maximum (FWHM) of the intrinsically symmetrical filament segments is ∼ 0.67 pc with the Plummer-like fitting, and ∼ 0.50 pc with the Gaussian fitting, respectively. The median FWHMs derived from the second-moment method for intrinsically symmetrical and asymmetrical profiles are ∼ 0.44 and 0.46 pc, respectively. Close association exists between the filamentary structures and the YSOs in the region.


Keywords ISM: clouds — ISM: individual objects (Orion A) — ISM: structure — stars: formation

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