ALMAGAL. VII. Cataloging Hierarchical Continuum Structure from Cores to Clumps across the Galactic Disk

Abstract Investigating the multiscale fragmentation of dense clumps into compact cores is essential for understanding the processes that govern the initial distribution of mass in stellar clusters and how high-mass stars (&gt;8 M ⊙ ) form. We present a catalog of the hierarchical continuum structure from 904 clumps observed in the ALMAGAL program, a high-resolution (0 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mover> <mml:mrow> <mml:mo>.</mml:mo> </mml:mrow> <mml:mrow> <mml:mtext>″</mml:mtext> </mml:mrow> </mml:mover> </mml:math> 15–0 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mover> <mml:mrow> <mml:mo>.</mml:mo> </mml:mrow> <mml:mrow> <mml:mtext>″</mml:mtext> </mml:mrow> </mml:mover> </mml:math> 8) 1.38 mm Atacama Large Millimeter/submillimeter Array large program targeting dense clumps capable of high-mass star formation throughout the Galactic disk. We use astrodendro , a dendrogram-based algorithm, on a uniform linear resolution (2000 au) version of the data to extract 5160 continuum structures with effective radii spanning 800–42000 au and estimated masses between 0.05–670 M ⊙ . With our large sample, we statistically examine differences in clump properties for regions with varying levels of hierarchical complexity. We find that clumps exhibiting the richest hierarchical morphology have distributions with higher dust temperatures, surface densities, luminosity-to-mass ( L / M ) ratios, and most massive core masses, indicating that these regions tend to be at later evolutionary stages. We find a positive correlation between the mass of cores from the ALMAGAL core catalog and the surface density of their surrounding structures identified in this work. However, this correlation is weaker for cores in more evolved clumps, where lower-mass cores can be found at higher local surface densities. This could indicate that some cores accrete mass less efficiently from the intraclump reservoir than others, despite the total available mass increasing over time, a scenario that is congruent with a clump-fed core accretion model.

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Publication Details

Journal
The Astrophysical Journal
Published
2026-02-17
DOI
https://doi.org/10.3847/1538-4357/ae2fec
Primary Topic
Astronomy and Astrophysical Research
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article
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article

ALMAGAL. VII. Cataloging Hierarchical Continuum Structure from Cores to Clumps across the Galactic Disk

Thomas Möller, Patricio Sanhueza, Aleksandra Kuznetsova, A. Nucara et al.
The Astrophysical Journal
Astronomy and Astrophysical Research
article

ALMAGAL. VII. Cataloging Hierarchical Continuum Structure from Cores to Clumps across the Galactic Disk

Thomas Möller, Patricio Sanhueza, Aleksandra Kuznetsova, A. Nucara, G. A. Fuller, Paul T. P. Ho, J. Wallace, K. L. J. Rygl, Patrick M. Koch, Pamela Klaassen, C. Mininni, G. Stroud, D. C. Lis, Á. Sánchez-Monge, S. Pezzuto, C. L. Brogan, A. Traficante, K. Johnston, A. Avison, Sheng‐Yuan Liu, Chi-Yan Law, Cara Battersby, M. T. Beltrán, Ralf S. Klessen, H. Beuther, M. Benedettini, T. R. Hunter, P. Schilke, D. Elia, L. Moscadelli, S. Molinari, A. Ahmadi, Beth Moody Jones, W. -J. Kim, F. van der Tak, R. Kuiper, Alessandro Coletta, Qizhou Zhang, Tianwei Zhang, Yu‐Nung Su, Leonardo Bronfman, E. Schisano, J. Allande, Taevis Kolz
article en

Abstract

Abstract Investigating the multiscale fragmentation of dense clumps into compact cores is essential for understanding the processes that govern the initial distribution of mass in stellar clusters and how high-mass stars (&gt;8 M ⊙ ) form. We present a catalog of the hierarchical continuum structure from 904 clumps observed in the ALMAGAL program, a high-resolution (0 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mover> <mml:mrow> <mml:mo>.</mml:mo> </mml:mrow> <mml:mrow> <mml:mtext>″</mml:mtext> </mml:mrow> </mml:mover> </mml:math> 15–0 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mover> <mml:mrow> <mml:mo>.</mml:mo> </mml:mrow> <mml:mrow> <mml:mtext>″</mml:mtext> </mml:mrow> </mml:mover> </mml:math> 8) 1.38 mm Atacama Large Millimeter/submillimeter Array large program targeting dense clumps capable of high-mass star formation throughout the Galactic disk. We use astrodendro , a dendrogram-based algorithm, on a uniform linear resolution (2000 au) version of the data to extract 5160 continuum structures with effective radii spanning 800–42000 au and estimated masses between 0.05–670 M ⊙ . With our large sample, we statistically examine differences in clump properties for regions with varying levels of hierarchical complexity. We find that clumps exhibiting the richest hierarchical morphology have distributions with higher dust temperatures, surface densities, luminosity-to-mass ( L / M ) ratios, and most massive core masses, indicating that these regions tend to be at later evolutionary stages. We find a positive correlation between the mass of cores from the ALMAGAL core catalog and the surface density of their surrounding structures identified in this work. However, this correlation is weaker for cores in more evolved clumps, where lower-mass cores can be found at higher local surface densities. This could indicate that some cores accrete mass less efficiently from the intraclump reservoir than others, despite the total available mass increasing over time, a scenario that is congruent with a clump-fed core accretion model.

The Astrophysical JournalVol. 998(2)
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Astronomy and Astrophysical Research
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