ALMAGAL

Context . A large fraction of stars form in clusters containing high-mass stars, which subsequently influences the local and galaxy-wide environment. Aims . Fundamental questions about the physics responsible for fragmenting molecular parsec-scale clumps into cores of a few thousand astronomical units (au) are still open, that only a statistically significant investigation with ALMA is able to address; for instance: the identification of the dominant agents that determine the core demographics, mass, and spatial distribution as a function of the physical properties of the hosting clumps, their evolutionary stage and the different Galactic environments in which they reside. The extent to which fragmentation is driven by clumps dynamics or mass transport in filaments also remains elusive. Methods . With the ALMAGAL project, we observed the 1.38 mm continuum and lines toward more than 1000 dense clumps in our Galaxy, with M ≥ 500 M ⊙ , Σ ≥ 0.1 g cm −2 and d ≤ 7.5 kiloparsec (kpc). Two different combinations of ALMA Compact Array (ACA) and 12-m array setups were used to deliver a minimum resolution of ∼1000 au over the entire sample distance range. The sample covers all evolutionary stages from infrared dark clouds (IRDCs) to H II regions from the tip of the Galactic bar to the outskirts of the Galaxy. With a continuum sensitivity of 0.1 mJy, ALMAGAL enables a complete study of the clump-to-core fragmentation process down to M ∼ 0.3 M ⊙ across the Galaxy. The spectral setup includes several molecular lines to trace the multiscale physics and dynamics of gas, notably CH 3 CN, H 2 CO, SiO, CH 3 OH, DCN, HC 3 N, and SO, among others. Results . We present an initial overview of the observations and the early science product and results produced in the ALMAGAL Consortium, with a first characterization of the morphological properties of the continuum emission detected above 5 σ in our fields. We used “perimeter-versus-area” and convex hull-versus-area metrics to classify the different morphologies. We find that more extended and morphologically complex (significantly departing from circular or generally convex) shapes are found toward clumps that are relatively more evolved and have higher surface densities. Conclusions . ALMAGAL is poised to serve as a game-changer for a number of specific issues in star formation: clump-to-core fragmentation processes, demographics of cores, core and clump gas chemistry and dynamics, infall and outflow dynamics, and disk detections. Many of these issues will be covered in the first generation of papers that closely follow on the present publication.

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Publication Details

Journal
Astronomy and Astrophysics
Published
2025-03-14
DOI
https://doi.org/10.1051/0004-6361/202452702
Citations
17
Primary Topic
Astronomy and Astrophysical Research
Type
article
Field-Weighted Citation Impact
20.26

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article

ALMAGAL

R.S. Klessen, J. Bally, L. Bronfman, R. Plume et al.
17 citations
Astronomy and Astrophysics
Astronomy and Astrophysical Research
20.26
article

ALMAGAL

R.S. Klessen, J. Bally, L. Bronfman, R. Plume, Manuel Merello, A. Nucara, G. A. Fuller, Paul T. P. Ho, Tong Zhang, T. Moeller, C. Battersby, F. Nakamura, L. Testi, J. Wallace, Bernd Alois Zimmermann, K. L. J. Rygl, T. Henning, A. J. Rigby, S.L. Lumsden, Patrick M. Koch, M. G. Hoare, P. Sanhueza, F. Fontani, A. S'anchez-Monge, P. Schilke, Q. Zhang, C. Mininni, P. Hennebelle, S. Walch, G. Stroud, W.-J. Kim, S. Pezzuto, H. Zinnecker, C. L. Brogan, K. Johnston, A. Avison, Sheng‐Yuan Liu, Chi-Yan Law, B. Svoboda, Susanne Pfalzner, M. R. A. Wells, M. Benedettini, Khean‐Lee Goh, T. R. Hunter, D. Lis, B. Jones, R. Cesaroni, U. Lebreuilly, D. Elia, Sheng‐Li Qin, L. Moscadelli, V. S. Veena, S. Molinari, S. J. Liu, A. Ahmadi, Yang Su, F. Wyrowski, Kee‐Tae Kim, F. van der Tak, E. Schisano, L. T. Maud, A. Traficante, R. Kuiper, Alessandro Coletta, F. De Angelis, M.T. Beltr'an, J. D. Soler, Ya‐Wen Tang, N. Peretto, Shaun D. Clarke, Pamela Klaassen, H. Beuther, Fernando Amaral, D. Walker, Tie Liu, P. Hatchfield
article en
17 citations

Abstract

Context . A large fraction of stars form in clusters containing high-mass stars, which subsequently influences the local and galaxy-wide environment. Aims . Fundamental questions about the physics responsible for fragmenting molecular parsec-scale clumps into cores of a few thousand astronomical units (au) are still open, that only a statistically significant investigation with ALMA is able to address; for instance: the identification of the dominant agents that determine the core demographics, mass, and spatial distribution as a function of the physical properties of the hosting clumps, their evolutionary stage and the different Galactic environments in which they reside. The extent to which fragmentation is driven by clumps dynamics or mass transport in filaments also remains elusive. Methods . With the ALMAGAL project, we observed the 1.38 mm continuum and lines toward more than 1000 dense clumps in our Galaxy, with M ≥ 500 M ⊙ , Σ ≥ 0.1 g cm −2 and d ≤ 7.5 kiloparsec (kpc). Two different combinations of ALMA Compact Array (ACA) and 12-m array setups were used to deliver a minimum resolution of ∼1000 au over the entire sample distance range. The sample covers all evolutionary stages from infrared dark clouds (IRDCs) to H II regions from the tip of the Galactic bar to the outskirts of the Galaxy. With a continuum sensitivity of 0.1 mJy, ALMAGAL enables a complete study of the clump-to-core fragmentation process down to M ∼ 0.3 M ⊙ across the Galaxy. The spectral setup includes several molecular lines to trace the multiscale physics and dynamics of gas, notably CH 3 CN, H 2 CO, SiO, CH 3 OH, DCN, HC 3 N, and SO, among others. Results . We present an initial overview of the observations and the early science product and results produced in the ALMAGAL Consortium, with a first characterization of the morphological properties of the continuum emission detected above 5 σ in our fields. We used “perimeter-versus-area” and convex hull-versus-area metrics to classify the different morphologies. We find that more extended and morphologically complex (significantly departing from circular or generally convex) shapes are found toward clumps that are relatively more evolved and have higher surface densities. Conclusions . ALMAGAL is poised to serve as a game-changer for a number of specific issues in star formation: clump-to-core fragmentation processes, demographics of cores, core and clump gas chemistry and dynamics, infall and outflow dynamics, and disk detections. Many of these issues will be covered in the first generation of papers that closely follow on the present publication.

Astronomy and AstrophysicsVol. 696
Tokyo Institute of Technology (JP), University of Rome Tor Vergata (IT), Leiden University (NL), Centre National de la Recherche Scientifique (FR), University of Leeds (GB), Institute of Astronomy and Astrophysics, Academia Sinica (TW), European Southern Observatory (DE), Jet Propulsion Laboratory (US), University of Connecticut (US), Pontificia Universidad Católica de Chile (CL), University of Calgary (CA), University of Groningen (NL), Forschungszentrum Jülich (DE), University of Cologne (DE), University of Colorado Boulder (US), Yunnan University (CN), National Institutes of Natural Sciences (JP), Université Paris Cité (FR), Heidelberg University (DE), National Radio Astronomy Observatory (US), Commissariat à l'Énergie Atomique et aux Énergies Alternatives (FR), Université Paris-Saclay (FR), Shanghai Astronomical Observatory (CN), Arcetri Astrophysical Observatory (IT), Korea Astronomy and Space Science Institute (KR), Harvard University Press (US), University of Manchester (GB), Universidad Autónoma de Chile (CL), Astrophysique, Instrumentation et Modélisation (FR), Max Planck Institute for Extraterrestrial Physics (DE), Institut d'Estudis Espacials de Catalunya (ES), Institute for Space Astrophysics and Planetology (IT), Laboratoire d’Etudes du Rayonnement et de la Matière en Astrophysique et Atmosphères (FR), Royal Observatory (GB), SKA Observatory (GB), Max Planck Institute for Astronomy (DE), Institute of Space Sciences (ES), Istituto di Radioastronomia di Bologna (IT), Center for Astrophysics Harvard & Smithsonian (US), CEA Paris-Saclay (FR), Institut de Ciència de Materials de Barcelona (ES), Max Planck Institute for Radio Astronomy (DE), National Astronomical Observatory of Japan (JP), Space Research Organisation Netherlands (NL), UK Astronomy Technology Centre (GB), University of Lincoln (GB), University of Duisburg-Essen (DE), University of Chile (CL), Cardiff University (GB), Sapienza University of Rome (IT), Korea University of Science and Technology (KR), University of Bologna (IT)
National Science Foundation, Smithsonian Institution, National Aeronautics and Space Administration, California Institute of Technology, National Radio Astronomy Observatory, European Commission, Deutsche Forschungsgemeinschaft, Korea Astronomy and Space Science Institute, National Astronomical Observatory of Japan, Universität zu Köln, Agencia Nacional de Investigación y Desarrollo, Jet Propulsion Laboratory, Smithsonian Astrophysical Observatory, Science and Technology Facilities Council, European Research Council, National Institutes of Natural Sciences, Agencia Estatal de Investigación
Openalex Percentile: Top 0%
Astronomy and Astrophysical Research
20.26
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