ALMAGAL

V. Relations between the core populations and the parent clump physical properties

¹ INAF – IAPS, via Fosso del Cavaliere, 100, 00133 Roma, Italy; Istituto Nazionale di Astrofisica (INAF)-Istituto di Astrofisica e Planetologia Spaziali, Via Fosso del Cavaliere 100, 00133 Roma, Italy
² Dipartimento di Fisica, Sapienza Università di Roma, Piazzale Aldo Moro 2, 00185 Roma, Italy
³ Institut de Ciències de l’Espai (ICE, CSIC), Campus UAB, Carrer de Can Magrans s/n, 08193 Bellaterra (Barcelona), Spain
⁴ Institut d’Estudis Espacials de Catalunya (IEEC), 08860 Castelldefels (Barcelona), Spain
⁵ Dipartimento di Fisica, Università di Roma Tor Vergata, Via della Ricerca Scientifica 1, 00133 Roma, Italy
⁶ Physikalisches Institut der Universität zu Köln, Zülpicher Str. 77, 50937 Köln, Germany
⁷ SKA Observatory, Jodrell Bank, Lower Withington, Macclesfield SK11 9FT, UK
⁸ Istituto Nazionale di Astrofisica (INAF), Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, Firenze, Italy
⁹ Max Planck Institute for Astronomy, Königstuhl 17, 69117 Heidelberg, Germany
¹⁰ Institute of Astronomy and Astrophysics, Academia Sinica, 11F of ASMAB, AS/NTU No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan
¹¹ Jodrell Bank Centre for Astrophysics, Department of Physics and Astronomy, The University of Manchester, Oxford Road, Manchester M13 9PL, UK
¹² Universität Heidelberg, Zentrum f|"ur Astronomie, Institut für Theoretische Astrophysik, Albert-Ueberle-Str. 2, 69120 Heidelberg, Germany
¹³ Universität Heidelberg, Interdisziplinäres Zentrum für Wissenschaftliches Rechnen, Im Neuenheimer Feld 205, 69120 Heidelberg, Germany
¹⁴ Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA
¹⁵ Elizabeth S. and Richard M. Cashin Fellow at Radcliffe Institute for Advanced Studies at Harvard University, 10 Garden Street, Cambridge, MA 02138, USA
¹⁶ Faculty of Physics, University of Duisburg-Essen, Lotharstraße 1, 47057 Duisburg, Germany
¹⁷ Université Paris-Saclay, Université Paris-Cité, CEA, CNRS, AIM, 91191 Gif-sur-Yvette, France
¹⁸ Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA
¹⁹ School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK
²⁰ Department of Astronomy, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan
²¹ SRON Netherlands Institute for Space Research, Landleven 12, 9747, AD Groningen, The Netherlands
²² Kapteyn Astronomical Institute, University of Groningen, Landleven 12, 9747 AD Groningen, The Netherlands
²³ INAF-Istituto di Radioastronomia & Italian ALMA Regional Centre, Via P. Gobetti 101, 40129 Bologna, Italy
²⁴ Centro de Astro-Ingeniería UC, Instituto de Astrofísica, Pontificia Universidad Católica de Chile, Avda Vicuña Mackenna 4860, Macul, Santiago, Chile
²⁵ Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany
²⁶ University of Connecticut, Department of Physics, 196A Auditorium Road, Unit 3046, Storrs, CT 06269, USA
²⁷ East Asian Observatory, 660 N. A’ohoku, Hilo, Hawaii, HI 96720, USA
²⁸ UK Astronomy Technology Centre, Royal Observatory Edinburgh, Blackford Hill, Edinburgh EH9 3HJ, UK
²⁹ Dipartimento di Fisica e Astronomia, Università degli Studi di Firenze, Via G. Sansone 1, 50019 Sesto Fiorentino, Firenze, Italy
³⁰ Departamento de Astronomía, Universidad de Chile, Casilla 36-D, Santiago, Chile
³¹ Max-Planck-Institute for Extraterrestrial Physics (MPE), Garching bei München, Germany
³² LUX, Observatoire de Paris, Université PSL, Sorbonne Université, CNRS, 75014 Paris, France
³³ Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Shanghai 200030, China
³⁴ Leiden Observatory, Leiden University, PO Box 9513, 2300 RA Leiden, The Netherlands
³⁵ National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903, USA
³⁶ School of Engineering and Physical Sciences, The University of Lincoln, Brayford Way, Lincoln LN6 7TS, UK
³⁷ INAF – Astronomical Observatory of Capodimonte, Via Moiariello 16, 80131 Napoli, Italy
³⁸ Dipartimento di Fisica e Astronomia, Alma Mater Studiorum – Università di Bologna Dipartimento di Fisica e Astronomia “Augusto Righi”, Via Gobetti 93/2, 40129, Bologna, Italy
³⁹ Center for Data and Simulation Science, University of Cologne, Germany
⁴⁰ Research Center for Astronomical computing, Zhejiang Laboratory, Hangzhou, China
⁴¹ Universidad Autonoma de Chile, Av Pedro de Valdivia 425, Providencia, Santiago de Chile, Chile

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Received: 26 March 2025
Accepted: 7 November 2025

Abstract

Context. The fragmentation of massive molecular clumps into smaller, potentially star-forming cores plays a key role in the processes of high-mass star formation. The ALMAGAL project, using the Atacama Large Millimeter/submillimeter Array (ALMA), offers highr-esolution data to investigate these processes across various evolutionary stages in the Galactic plane.

Aims. This study aims at correlating the fragmentation properties of massive clumps, obtained from ALMA observations, with their global physical parameters (e.g., mass, surface density, and temperature) and evolutionary indicators (e.g., luminosity-to-mass ratio and bolometric temperature) obtained from Herschel observations. It seeks to assess whether the cores evolve in number and mass in tandem with their host clumps and to determine the possible factors influencing the formation of massive cores (M > 24 M_⊙).

Methods. We analyzed the masses of 6348 fragments, estimated from 1.4 mm continuum data for 1007 ALMAGAL clumps. Leveraging this unprecedentedly large dataset, we evaluated statistical relationships between clump parameters, estimated over ~0.1 pc scales, and fragment properties, corresponding to scales of a few thousand astronomical units, while accounting for potential biases related to distance and observational resolution. Our results were further compared with predictions from numerical simulations.

Results. The fragmentation level correlates preferentially with clump surface density, supporting a scenario of density-driven fragmentation; however, it does not show any clear dependence on total clump mass. Both the mass of the most massive core and the core formation efficiency exhibit a broad range and increase, on average, by an order of magnitude across intervals defined by evolutionary indicators such as clump-dust temperature and the luminosity-to-mass ratio. This suggests that core growth continues throughout clump evolution, favoring clump-fed over core-fed theoretical scenarios. However, significant scatter in these relationships indicates that multiple factors, including magnetic fields, turbulence, and stellar feedback, not quantifiable with continuum data, influence fragmentation, as also suggested by comparison with numerical simulations.