ALMA-IMF

XVI. Mass-averaged temperature of cores and protostellar luminosities in the ALMA-IMF protoclusters

¹ Univ. Grenoble Alpes, CNRS, IPAG, 38000 Grenoble, France
² Instituto de Radioastronomía y Astrofísica, Universidad Nacional Autónoma de México, Morelia, Michoacán 58089, México
³ INAF, Osservatorio Astrofisico di Arcetri, Largo Enrico Fermi 5, 50125 Firenze, Italy
⁴ Laboratoire de Physique de l’École Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université de Paris, Paris, France
⁵ Observatoire de Paris, PSL University, Sorbonne Université, LERMA, 75014 Paris, France
⁶ Université Paris-Saclay, CNRS, Institut d’Astrophysique Spatiale, 91405 Orsay, France
⁷ Laboratoire d’astrophysique de Bordeaux, Univ. Bordeaux, CNRS, B18N, allée Geoffroy Saint-Hilaire, 33615 Pessac, France
⁸ Departamento de Astronomía, Universidad de Concepción, Casilla 160-C, Concepción, Chile
⁹ Franco-Chilean Laboratory for Astronomy, IRL 3386, CNRS and Universidad de Chile, Santiago, Chile
¹⁰ Department of Astronomy, University of Florida, PO Box 112055, USA
¹¹ Université Paris-Saclay, Université Paris Cité, CEA, CNRS, AIM, 91191 Gif-sur-Yvette, France
¹² Departments of Astronomy and Chemistry, University of Virginia, Charlottesville, VA 22904, USA
¹³ Departamento de Astronomía, Universidad de Chile, Casilla 36-D, Santiago, Chile
¹⁴ Institute of Astronomy, National Tsing Hua University, Hsinchu 30013, Taiwan
¹⁵ SKA Observatory, Jodrell Bank, Lower Withington, Macclesfield, SK11 9FT, United Kingdom
¹⁶ Instituto Argentino de Radioastronomía (CCT-La Plata, CONICET; CICPBA), C.C. No. 5, 1894, Villa Elisa, Buenos Aires, Argentina
¹⁷ Department of Astronomy, Yunnan University, Kunming 650091, People’s Republic of China
¹⁸ CSMES, The American University of Paris, PL111, 2 bis, passage Landrieu, 75007 Paris, France
¹⁹ TNU Observatory, Tay Nguyen University, 567 Le Duan, Ea Tam, Buon Ma Thuot City, Dak Lak 630000, Vietnam
²⁰ National Astronomical Observatory of Japan, National Institutes of Natural Sciences, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan
²¹ Department of Astronomical Science, SOKENDAI (The Graduate University for Advanced Studies), 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan

^★ Corresponding author; frederique.motte@univ-grenoblealpes.fr

Received: 20 August 2024
Accepted: 11 November 2024

Abstract

Context. The ALMA-IMF Large Program imaged 15 massive protoclusters down to a resolution of ~2 kau scales, identifying about 10³ star-forming cores. The mass and luminosity of these cores, which are fundamental physical characteristics, are difficult to determine, a problem greatly exacerbated at the distances ≥2 kpc of ALMA-IMF protoclusters.

Aims. We combined new datasets and radiative transfer modeling to characterize these cores. We estimated their mass-averaged temperature and the masses these estimates imply. For one-sixth of the sample, we measured the bolometric luminosities, implementing deblending corrections when necessary.

Methods. We used spectral energy distribution (SED) analysis obtained with the point process mapping (PPMAP) Bayesian procedure, which aims to preserve the best angular resolution of the input data. We extrapolated the luminosity and dust temperature images provided by PPMAP at 2.5″ resolution to estimate those of individual cores, which were identified at higher angular resolution. To do this, we applied approximate radiative transfer relationships between the luminosity of a protostar and the temperature of its surrounding envelope and between the external heating of prestellar cores and their temperatures.

Results. For the first time, we provide data-informed estimates of dust temperatures for 882 cores identified with ALMA-IMF: 17–31 K and 28–79 K (5th and 95th percentiles, up to 127 K) for the 616 prestellar and 266 protostellar cores, respectively. We also measured protostellar luminosities spanning 20–80 000 L_⊙.

Conclusions. Dust temperatures previously estimated from SED-based analyses at a comparatively lower resolution validate our method. For hot cores, on the other hand, we estimated systematically lower temperatures than studies based on complex organic molecules. We established a mass-luminosity evolutionary diagram, for the first time at the core spatial resolution and for a large sample of intermediate- to high-mass protostellar cores. The ALMA-IMF data favor a scenario in which protostars accrete their mass from a larger mass reservoir than their host cores.