Structures of GMC W 37

Abstract

We carried out observations toward the giant molecular cloud W 37 with the $J=1-0$ transitions of ${}^{12}$CO, ${}^{13}$CO, and C${}^{18}$O using the 13.7 m single-dish telescope at the Delingha station of Purple Mountain Observatory. Based on the three CO lines, we calculated the column densities, cloud masses for the molecular clouds with radial velocities at around $+20{\mathrm{kms}}^{-1}$. The gas mass of W 37, calculated from ${}^{13}$CO emission, is $1.7\times 10^5{M}_{\odot }$, above the criteria of giant molecular cloud. The dense ridge of W 37 is a dense filament, which is supercritical in linear mass ratio. Dense clumps found by C${}^{18}$O emission are aligned along the dense ridge with a regular interval about 2.8 pc, similar to the clump separation caused by large-scale `sausage instability'. We confirm the identification of the giant molecular filament (GMF) G 18.0-16.8 by \cite{2014A&A...568A..73R} and find a new giant filament, G16.5-15.8, located in the west 0.8 degree of G 18.0-16.8. Both GMFs are not gravitationally bound, as indicated by their low linear mass ratio ($\sim 80M_{\odot }{\mathrm{pc}}^{-1}$). We compared the gas temperature map with the dust temperature map from \emph{Herschel} images, and find similar structures. The spatial distributions of class I objects and the dense clumps is reminiscent of triggered star formation occurring in the northwestern part of W 37, which is close to NGC 6611.

accepted for publication in RAA; any comment is welcome

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Cited by in corpus (6)

• The Milky Way Imaging Scroll Painting (MWISP): Project Details and Initial Results from the Galactic Longitude of 25.8deg to 49.7deg
• Gamma-ray observation towards the young massive star cluster NGC 6618 in the M17 region
• SOFIA FEEDBACK Survey: The Pillars of Creation in [C II] and Molecular Lines
• Molecular Clump Extraction Algorithm Based on Local Density Clustering
• Investigations of MWISP Filaments. I. Filament Identification and Analysis Algorithms, and Source Catalogue
• Investigations of MWISP Bubbles: Identification and Analysis of Enclosed Molecular Bubbles by Weight Fields