ALMAGAL

III. Compact source catalog: Fragmentation statistics and physical evolution of the core population

¹ INAF – Istituto di Astrofisica e Planetologia Spaziali (IAPS), Via Fosso del Cavaliere 100, 00133 Roma, Italy
² Dipartimento di Fisica, Sapienza Università di Roma, Piazzale Aldo Moro 2, 00185 Rome, Italy
³ Institute of Space Sciences (ICE-CSIC), Carrer de Can Magrans s/n, 08193 Barcelona, Spain
⁴ Institut d’Estudis Espacials de Catalunya (IEEC), 08860 Castelldefels (Barcelona), Spain
⁵ Physikalisches Institut der Universität zu Köln, Zülpicher Str. 77, 50937 Köln, Germany
⁶ University of Connecticut, Department of Physics, 2152 Hillside Road, Unit 3046 Storrs, CT 06269, USA
⁷ Jodrell Bank Centre for Astrophysics, Oxford Road, The University of Manchester, Manchester M13 9PL, UK
⁸ Max Planck Institute for Astronomy, Königstuhl 17, 69117 Heidelberg, Germany
⁹ Center for Astrophysics, Harvard & Smithsonian, 60 Garden Street, Cambridge, MA 02138, USA
¹⁰ INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125, Firenze, Italy
¹¹ Universität Heidelberg, Zentrum für Astronomie, Institut für Theoretische Astrophysik, Albert-Ueberle-Str. 2, 69120 Heidelberg, Germany
¹² Universität Heidelberg, Interdisziplinäres Zentrum für Wissenschaftliches Rechnen, Im Neuenheimer Feld 205, 69120 Heidelberg, Germany
¹³ Center for Data and Simulation Science, University of Cologne, Germany
¹⁴ Laboratoire d’Études du Rayonnement et de la Matière en Astrophysique et Atmosphères (LERMA), Observatoire de Paris, Meudon, France
¹⁵ Max-Planck-Institute for Extraterrestrial Physics (MPE), Garching bei München, Germany
¹⁶ SKA Observatory, Jodrell Bank, Lower Withington, Macclesfield SK11 9FT, UK
¹⁷ UK ALMA Regional Centre Node M13 9PL, UK
¹⁸ National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903, USA
¹⁹ Institute of Astronomy and Astrophysics, Academia Sinica, 11F of ASMAB, AS/NTU No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan
²⁰ Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA
²¹ Université Paris-Saclay, Université Paris-Cité, CEA, CNRS, AIM, 91191 Gif-sur-Yvette, France
²² East Asian Observatory, 660 N. A’ohoku, Hilo, Hawaii, HI 96720, USA
²³ School of Engineering and Physical Sciences, Isaac Newton Building, University of Lincoln, Brayford Pool, Lincoln LN6 7TS, UK
²⁴ UK Astronomy Technology Centre, Royal Observatory Edinburgh, Blackford Hill, Edinburgh EH9 3HJ, UK
²⁵ Faculty of Physics, University of Duisburg-Essen, Lotharstraße 1, 47057 Duisburg, Germany
²⁶ Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Shanghai 200030, China
²⁷ School of Physics and Astronomy, The University of Leeds, Woodhouse Lane, Leeds LS2 9JT, UK
²⁸ INAF - Astronomical Observatory of Capodimonte, Via Moiariello 16, 80131 Napoli, Italy
²⁹ Dipartimento di Fisica, Università di Roma Tor Vergata, Via della Ricerca Scientifica 1, 00133 Roma, Italy
³⁰ Cardiff Hub for Astrophysics Research & Technology, School of Physics & Astronomy, Cardiff University, Queen’s Buildings, The Parade, Cardiff CF24 3AA, UK
³¹ INAF-Istituto di Radioastronomia, Via P. Gobetti 101, 40129 Bologna, Italy
³² National Astronomical Observatory of Japan, National Institutes of Natural Sciences, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan
³³ Department of Earth and Planetary Sciences, Institute of Science Tokyo, Meguro, Tokyo 152-8551, Japan
³⁴ Kapteyn Astronomical Institute, University of Groningen, 9700, AV Groningen, The Netherlands
³⁵ SRON Netherlands Institute for Space Research, Landleven 12, 9747, AD Groningen, The Netherlands
³⁶ Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany
³⁷ Leiden Observatory, Leiden University, PO Box 9513, 2300 RA Leiden, The Netherlands
³⁸ Departamento de Astronomía, Universidad de Chile, Casilla 36-D, Santiago, Chile
³⁹ Dipartimento di Fisica e Astronomia, Alma Mater Studiorum – Università di Bologna,
⁴⁰ Universidad Autonoma de Chile, Avda Pedro de Valdivia 425, Santiago de Chile, Chile

^★ Corresponding author; alessandro.coletta@inaf.it

Received: 22 October 2024
Accepted: 19 January 2025

Abstract

The physical mechanisms behind the fragmentation of high-mass dense clumps into compact star-forming cores and the properties of these cores are fundamental topics that are heavily investigated in current astrophysical research. The ALMAGAL survey provides the opportunity to study this process at an unprecedented level of detail and statistical significance, featuring high-angular resolution 1.38 mm ALMA observations of 1013 massive dense clumps at various Galactic locations. These clumps cover a wide range of distances (~2–8 kpc), masses (~10²–10⁴ M_⊙), surface densities (0.1–10 g cm⁻²), and evolutionary stages (luminosity over mass ratio indicator of ~0.05 < L/M < 450L_⊙/M_⊙). Here, we present the catalog of compact sources obtained with the CuTEx algorithm from continuum images of the full ALMAGAL clump sample combining ACA-7 m and 12 m ALMA arrays, reaching a uniform high median spatial resolution of ~1400 au (down to ~800 au). We characterize and discuss the revealed fragmentation properties and the photometric and estimated physical parameters of the core population. The ALMAGAL compact source catalog includes 6348 cores detected in 844 clumps (83% of the total), with a number of cores per clump between 1 and 49 (median of 5). The estimated core diameters are mostly within ~800–3000 au (median of 1700 au). We assigned core temperatures based on the L/M of the hosting clump, and obtained core masses from 0.002 to 345 M_⊙ (complete above 0.23 M_⊙), exhibiting a good correlation with the core radii (M ∝ R^2.6). We evaluated the variation in the core mass function (CMF) with evolution as traced by the clump L/M, finding a clear, robust shift and change in slope among CMFs within subsamples at different stages. This finding suggests that the CMF shape is not constant throughout the star formation process, but rather it builds (and flattens) with evolution, with higher core masses reached at later stages. We found that all cores within a clump grow in mass on average with evolution, while a population of possibly newly formed lower-mass cores is present throughout. The number of cores increases with the core masses, at least until the most massive core reaches ~10M_⊙. More generally, our results favor a clump-fed scenario for high-mass star formation, in which cores form as low-mass seeds, and then gain mass while further fragmentation occurs in the clump.