Dynamical accretion flows

ALMAGAL: Flows along filamentary structures in high-mass star-forming clusters

¹ Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany
² INAF-Istituto di Astrofisica e Planetologia Spaziale, Via Fosso del Cavaliere 100, 00133 Roma, Italy
³ I. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, 50937 Köln, Germany
⁴ University of Connecticut, Department of Physics, 2152 Hillside Road, Unit 3046, Storrs, CT 06269, USA
⁵ Institute of Astronomy and Astrophysics, Academia Sinica, Taipei 10617, Taiwan
⁶ East Asian Observatory, 660 N. A’ohoku, Hilo, Hawaii, HI 96720, USA
⁷ Institut de Ciéncies de l’Espai (ICE, CSIC), Can Magrans s/n, 08193 Bellaterra, Barcelona, Spain
⁸ Institut d’Estudis Espacials de Catalunya (IEEC), Barcelona, Spain
⁹ Universität Heidelberg, Zentrum für Astronomie, Institut für Theoretische Astrophysik, Heidelberg, Germany
¹⁰ Universität Heidelberg, Interdisziplinäres Zentrum für Wissenschaftliches Rechnen, Heidelberg, Germany
¹¹ Harvard-Smithsonian Center for Astrophysics, 160 Garden St, Cambridge, MA 02420, USA
¹² Center for Data and Simulation Science, University of Cologne, Cologne, Germany
¹³ INAF – Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125 Firenze, Italy
¹⁴ Jodrell Bank Centre for Astrophysics & UK ALMA Regional Centre Node, School of Physics & Astronomy, University of Manchester, Manchester M13 9PL, UK
¹⁵ Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA
¹⁶ SRON Netherlands Institute for Space Research, Landleven 12, 9747 AD Groningen, The Netherlands
¹⁷ Kapteyn Astronomical Institute, University of Groningen, Groningen, The Netherlands
¹⁸ UK Astronomy Technology Centre, Royal Observatory Edinburgh, Blackford Hill, Edinburgh EH9 3HJ, UK
¹⁹ National Radio Astronomy Observatory (NRAO), 520 Edgemont Rd, Charlottesville, VA 22903, USA
²⁰ UK ALMA Regional Centre Node, Manchester M13 9PL, UK
²¹ SKA Observatory, Jodrell Bank, Lower Withington, Macclesfield SK11 9FT, UK
²² National Astronomical Observatory of Japan, National Institutes of Natural Sciences, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan
²³ Department of Astronomical Science, SOKENDAI (The Graduate University for Advanced Studies), 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan
²⁴ Dipartimento di Fisica, Universita di Roma La Sapienza, Piazzale Aldo Moro 2, 00185 Roma, Italy
²⁵ Faculty of Physics, University of Duisburg-Essen, Duisburg, Germany
²⁶ Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Shanghai 200030, PR China
²⁷ Centre for Astrochemical Studies, Max-Planck-Institute for Extraterrestrial Physics, Giessenbachstrasse 1, 85748 Garching, Germany
²⁸ LERMA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universite, 92190 Meudon, France
²⁹ INAF-Istituto di Radioastronomia & Italian ALMA Regional Centre, Via P. Gobetti 101, 40129 Bologna, Italy
³⁰ Max-Planck-Institut fur Radioastronomie (MPIfR), Auf dem Hügel 69, 53121 Bonn, Germany
³¹ Department of Astrophysical and Planetary Sciences, University of Colorado, Boulder, CO 80389, USA
³² Leiden Observatory, Leiden University, PO Box 9513 2300 RA Leiden, The Netherlands
³³ Departamento de Astronomía, Universidad de Chile, Santiago, Chile
³⁴ European Southern Observatory, Karl-Schwarzschild-Strasse 2, 85748 Garching, Germany
³⁵ Department of Space, Earth & Environment, Chalmers University of Technology, 412 96 Gothenburg, Sweden
³⁶ Dipartimento di Fisica e Astronomia “Augusto Righi”, Viale Berti Pichat 6/2, Bologna, Italy
³⁷ Universidad Autónoma de Chile, Nucleo Astroquimica y Astrofisica, Avda Pedro de Valdivia 425, Providencia, Santiago de Chile, Chile
³⁸ Max Planck Institute for Extraterrestrial Physics, Giessenbachstraße 1, 85749 Garching bei München, Germany
³⁹ School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK

^⋆ Corresponding author; wells@mpia.de.

Received: 29 February 2024
Accepted: 7 August 2024

Abstract

Context. Investigating the flow of material along filamentary structures towards the central core can help provide insights into high-mass star formation and evolution.

Aims. Our main motivation is to answer the question of what the properties of accretion flows are in star-forming clusters. We used data from the ALMA Evolutionary Study of High Mass Protocluster Formation in the Galaxy (ALMAGAL) survey to study 100 ALMAGAL regions at a ∼1″ resolution, located between ∼2 and 6 kpc.

Methods. Making use of the ALMAGAL ∼1.3 mm line and continuum data, we estimated flow rates onto individual cores. We focus specifically on flow rates along filamentary structures associated with these cores. Our primary analysis is centered around position velocity cuts in H₂CO (3_0, 3–2_0, 2), which allow us to measure the velocity fields surrounding these cores. Combining this work with column density estimates, we were able to derive the flow rates along the extended filamentary structures associated with cores in these regions.

Results. We selected a sample of 100 ALMAGAL regions, covering four evolutionary stages from quiescent to protostellar, young stellar objects (YSOs), and HII regions (25 each). Using a dendrogram and line analysis, we identify a final sample of 182 cores in 87 regions. In this paper, we present 728 flow rates for our sample (4 per core), analysed in the context of evolutionary stage, distance from the core, and core mass. On average, for the whole sample, we derived flow rates on the order of ∼10⁻⁴ M_⊙ yr⁻¹ with estimated uncertainties of ±50%. We see increasing differences in the values among evolutionary stages, most notably between the less evolved (quiescent and protostellar) and more evolved (YSO and HII region) sources and we also see an increasing trend as we move further away from the centre of these cores. We also find a clear relationship between the calculated flow rates and core masses ∼M^2/3, which is in line with the result expected from the tidal-lobe accretion mechanism. The significance of these relationships is tested with Kolmogorov–Smirnov and Mann-Whitney U tests.

Conclusions. Overall, we see an increasing trend in the relationships between the flow rate and the three investigated parameters, namely: evolutionary stage, distance from the core, and core mass.