ALMA–IMF

V. Prestellar and protostellar core populations in the W43 cloud complex^★

¹ Instituto de Radioastronomía y Astrofísica, Universidad Nacional Autónoma de México, Morelia, Michoacán 58089, Mexico
e-mail: t.nony@irya.unam.mx
² Univ. Grenoble Alpes, CNRS, IPAG, 38000 Grenoble, France
³ Departamento de Astronomía, Universidad de Concepción, Casilla 160-C, Concepción, Chile
⁴ Laboratoire d’astrophysique de Bordeaux, Univ. Bordeaux, CNRS, B18N, allée Geoffroy Saint-Hilaire, 33615 Pessac, France
⁵ Department of Astronomy, University of Florida, PO Box 112055, Gainesville, FL 32611-2055, USA
⁶ National Astronomical Observatory of Japan, National Institutes of Natural Sciences, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan
⁷ Department of Astronomical Science, SOKENDAI (The Graduate University for Advanced Studies), 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan
⁸ Instituto Argentino de Radioastronomía (CCT-La Plata, CONICET; CICPBA), C.C. No. 5, 1894, Villa Elisa, Buenos Aires, Argentina
⁹ S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata 700106, India
¹⁰ Departamento de Astronomía, Universidad de Chile, Casilla 36-D, Santiago, Chile
¹¹ Departament de Física Quàntica i Astrofísica (FQA), Universitat de Barcelona (UB), c. Martí i Franquès, 1, 08028 Barcelona, Spain
¹² Institut de Ciències del Cosmos (ICCUB), Universitat de Barcelona (UB), c. Martí i Franquès, 1, 08028 Barcelona, Spain
¹³ Institut d’Estudis Espacials de Catalunya (IEEC), c. Gran Capità 2–4, 08034 Barcelona, Spain
¹⁴ Herzberg Astronomy and Astrophysics Research Centre, National Research Council of Canada, 5071 West Saanich Road, Victoria, BC V9E 2E7, Canada
¹⁵ Laboratoire de Physique de l’École Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris Cité, 75005 Paris, France
¹⁶ Observatoire de Paris, PSL University, Sorbonne Université, LERMA, 75014 Paris, France
¹⁷ Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Shanghai 200030, PR China
¹⁸ Institute of Astronomy and Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
¹⁹ School of Physics and Astronomy, Cardiff University, Queen’s Buildings, The Parade, Cardiff CF24 3AA, UK
²⁰ Department of Astronomy, University of Virginia, Charlottesville, VA 22904, USA

Received: 17 August 2022
Accepted: 12 January 2023

Abstract

Context. The origin of the stellar initial mass function (IMF) and its relation with the core mass function (CMF) are actively debated issues with important implications in astrophysics. Recent observations in the W43 molecular complex of top-heavy CMFs, with an excess of high-mass cores compared to the canonical mass distribution, raise questions about our understanding of the star formation processes and their evolution in space and time.

Aims. We aim to compare populations of protostellar and prestellar cores in three regions imaged in the ALMA-IMF Large Program.

Methods. We created an homogeneous core catalogue in W43, combining a new core extraction in W43-MM1 with the catalogue of W43-MM2&MM3 presented in a previous work. Our detailed search for protostellar outflows enabled us to identify between 23 and 30 protostellar cores out of 127 cores in W43-MM1 and between 42 and 51 protostellar cores out of 205 cores in W43-MM2&MM3. Cores with neither outflows nor hot core emission are classified as prestellar candidates.

Results. We found a similar fraction of cores which are protostellar in the two regions, about 35%. This fraction strongly varies in mass, from f_pro ≃ 15–20% at low mass, between 0.8 and 3 M_⊙ up to f_pro ≃ 80% above 16 M_⊙. Protostellar cores are found to be, on average, more massive and smaller in size than prestellar cores. Our analysis also revealed that the high-mass slope of the prestellar CMF in W43, α = -1.46_-0.19^+0.12, is consistent with the Salpeter slope, and thus the top-heavy form measured for the global CMF, α = −0.96 ± 0.09, is due to the protostellar core population.

Conclusions. Our results could be explained by ‘clump-fed’ models in which cores grow in mass, especially during the protostellar phase, through inflow from their environment. The difference between the slopes of the prestellar and protostellar CMFs moreover implies that high-mass cores grow more in mass than low-mass cores.