Formation of a low-mass galaxy from star clusters in a 600-million-year-old Universe
The most distant galaxies detected were seen when the Universe was a scant 5% of its current age. At these times, progenitors of galaxies such as the Milky Way were about 10,000 times less massive. Using the James Webb Space Telescope (JWST) combined with magnification from gravitational lensing, these low-mass galaxies can not only be detected but also be studied in detail. Here we present JWST observations of a strongly lensed galaxy at z<sub>spec</sub> = 8.296 ± 0.001, showing massive star clusters (the Firefly Sparkle) cocooned in a diffuse arc in the Canadian Unbiased Cluster Survey (CANUCS)<sup>1</sup>. The Firefly Sparkle exhibits traits of a young, gas-rich galaxy in its early formation stage. The mass of the galaxy is concentrated in 10 star clusters (49-57% of total mass), with individual masses ranging from 10<sup>5</sup>M<sub>⊙</sub> to 10<sup>6</sup>M<sub>⊙</sub>. These unresolved clusters have high surface densities (>10<sup>3</sup>M<sub>⊙</sub> pc<sup>-</sup><sup>2</sup>), exceeding those of Milky Way globular clusters and young star clusters in nearby galaxies. The central cluster shows a nebular-dominated spectrum, low metallicity, high gas density and high electron temperature, hinting at a top-heavy initial mass function. These observations provide our first spectrophotometric view of a typical galaxy in its early stages, in a 600-million-year-old Universe.
Authors
- Gaël Noirot
- Swara Ravindranath (ORCID: https://orcid.org/0000-0002-5269-6527)
- Vivian Yun Yan Tan (ORCID: https://orcid.org/0000-0002-3503-8899)
- Jasleen Matharu (ORCID: https://orcid.org/0000-0002-7547-3385)
- Camilla Pacifici (ORCID: https://orcid.org/0000-0003-4196-0617)
- Maruša Bradač (ORCID: https://orcid.org/0000-0001-5984-0395)
- Johannes Zabl (ORCID: https://orcid.org/0000-0002-9842-6354)
- G. Desprez (ORCID: https://orcid.org/0000-0001-8325-1742)
- Roberto Abraham (ORCID: https://orcid.org/0000-0002-4542-921X)
- Adam Muzzin (ORCID: https://orcid.org/0000-0002-9330-9108)
- Chris J. Willott (ORCID: https://orcid.org/0000-0002-4201-7367)
- Ghassan T. E. Sarrouh (ORCID: https://orcid.org/0000-0001-8830-2166)
- Vicente Estrada-Carpenter (ORCID: https://orcid.org/0000-0001-8489-2349)
- Yoshihisa Asada (ORCID: https://orcid.org/0000-0003-3983-5438)
- Kartheik G. Iyer (ORCID: https://orcid.org/0000-0001-9298-3523)
- Marcin Sawicki (ORCID: https://orcid.org/0000-0002-7712-7857)
- Nicholas S. Martis (ORCID: https://orcid.org/0000-0003-3243-9969)
- Nusrath Jahan (ORCID: https://orcid.org/0009-0004-7069-1780)
- Victoria Strait (ORCID: https://orcid.org/0000-0002-6338-7295)
- Lamiya Mowla (ORCID: https://orcid.org/0000-0002-8530-9765)
- Gabriel Brammer (ORCID: https://orcid.org/0000-0003-2680-005X)
- Gregor Rihtaršič (ORCID: https://orcid.org/0009-0009-4388-898X)
Institutions
- Herzberg Institute of Astrophysics (CA)
- University of Copenhagen (DK)
- Space Telescope Science Institute (US)
- Goddard Space Flight Center (US)
- Shahjalal University of Science and Technology (BD)
- University of Ljubljana (SI)
- University of Toronto (CA)
- Wellesley College (US)
- York University (CA)
- Kyoto University (JP)
- Independent University, Bangladesh (BD)
- Astronomy and Space (AU)
- Deleted Institution
- Saint Mary's University (CA)
- Columbia University (US)
Publication Details
- Journal
- Nature
- Published
- 2024-12-11
- DOI
- https://doi.org/10.1038/s41586-024-08293-0
- Citations
- 48
- Primary Topic
- Galaxies: Formation, Evolution, Phenomena
- Type
- article
- Field-Weighted Citation Impact
- 15.91
Funders
- National Aeronautics and Space Administration
- Canadian Foundation for AIDS Research
- Canarie
- Space Telescope Science Institute
- University of Toronto
- Javna Agencija za Raziskovalno Dejavnost RS
- Alliance de recherche numérique du Canada
- Canadian Space Agency
- Natural Sciences and Engineering Research Council of Canada
- Japan Society for the Promotion of Science