RJ-plots: An improved method to classify structures objectively

Abstract

The interstellar medium is highly structured, presenting a range of morphologies across spatial scales. The large data sets resulting from observational surveys and state-of-the-art simulations studying these hierarchical structures means that identification and classification must be done in an automated fashion to be efficient. Here we present RJ-plots, an improved version of the automated morphological classification technique J-plots developed by Jaffa et al. (2018). This method allows clear distinctions between quasi-circular/elongated structures and centrally over/under-dense structures. We use the recent morphological SEDIGISM catalogue of Neralwar et al. (2022) to show the improvement in classification resulting from RJ-plots, especially for ring-like and concentrated cloud types. We also find a strong correlation between the central concentration of a structure and its star formation efficiency and dense gas fraction, as well as a lack of correlation with elongation. Furthermore, we use the accreting filament simulations of Clarke et al. (2020) to highlight a multi-scale application of RJ-plots, finding that while spherical structures become more common at smaller scales they are never the dominant structure down to $r\sim 0.03$ pc.

11 pages, 9 figures, accepted by MNRAS

References in corpus (9)

• Array Programming with NumPy
• Structural Analysis of Molecular Clouds: Dendrograms
• FellWalker - a Clump Identification Algorithm
• The identification of filaments on far infrared and submillimiter images. Morphology, physical conditions and relation with star formation of filamentary structure
• The SEDIGISM survey: first data release and overview of the Galactic structure
• The Hi-GAL catalogue of dusty filamentary structures in the Galactic Plane
• The SEDIGISM survey: Molecular clouds in the inner Galaxy
• SEDIGISM-ATLASGAL: Dense Gas Fraction and Star Formation Efficiency Across the Galactic Disk
• The hierarchical fragmentation of filaments and the role of sub-filaments

Cited by in corpus (1)

• A Herschel study of G214.5-1.8: a young, cold and quiescent giant molecular filament on the shell of a HI superbubble