Atomic and molecular gas in the Milky Way. I. Structure decomposition

2025/09/20 by Xin Liu, Liu, Xin, Fujun Du +1 · 1 citation
Physics and Astronomy · #Astro and Planetary Science #Astronomical and nuclear sciences #Astrophysics of Galaxies (astro-ph.GA) #FOS: Physical sciences #Stellar, planetary, and galactic studies

paper · pdf · doi:10.48550/arxiv.2509.16572

openalex publication_date 2025/09/20 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

Abstract

We present GDCluster, a fully automated algorithm for decomposing spectral-line datacube of interstellar gas into coherent structures. Assuming a multi-Gaussian nature of observed spectra, GDCluster employs and augments the derivative spectroscopy technique for precise parameter estimation, incorporates spatial-continuity constraints during spectral fitting, and extends these constraints to spatial clustering. This approach effectively resolves velocity blending structures in PPV space-particularly critical for ubiquitous HI spectra where emissions from multiple phases are severely blended. Applied to the all-sky HI4PI data, a 10 degree times 10 degree CRAFTS survey region, and a 45 degree times 10 degree MWISP survey region, GDCluster extracts 45,299, 2247, and 47,119 structures in HI and CO (1-0), respectively. Comparative analyses demonstrate GDCluster's superiority over DBSCAN in separating overlapping spectra with complex velocity components.

Citations

• ISMGCC: Finding Gas Structures in Molecular Interstellar Medium Using Gaussian Decomposition and Graph Theory
• The Formation of Milky Way "Bones": Ubiquitous HI Narrow Self-Absorption Associated with CO Emission
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• H I in the Galaxy

Cited by

• How is Cold Gas Loaded into Galactic Nuclear Outflows?

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