Nature Astronomy

Identification of more than 40 gravitationally magnified stars in a galaxy at redshift 0.725

Yoshinobu Fudamoto ^{1, 2}

Fengwu Sun ^{2, 3}

Jose M. Diego ⁴

Liang Dai ⁵

Masamune Oguri ^{1, 6}

Adi Zitrin ⁷

Erik Zackrisson ^{8, 9}

Mathilde Jauzac ^{10, 11, 12, 13}

David J Lagattuta ^{10, 11}

Eiichi EGAMI ²

Edoardo Iani ¹⁴

Rogier A. Windhorst ¹⁵

Katsuya T. Abe ¹

Franz Bauer ^{16, 17, 18}

Fuyan Bian ¹⁹

Rachana Bhatawdekar ²⁰

Thomas J Broadhurst ^{21, 22, 23}

Zheng Cai ²⁴

Chian-Chou Chen ²⁵

Wenlei Chen ²⁶

Seth H. Cohen ¹⁵

Christopher J. Conselice ²⁷

Daniel Espada ^{28, 29}

Nicholas Foo ¹⁵

Brenda L. Frye ³⁰

Seiji Fujimoto ³¹

L. J. Furtak ⁷

Miriam Golubchik ⁷

Tiger Yu-Yang Hsiao ³²

J.-B. Jolly ³³

Hiroki Kawai ³⁴

Patrick L. Kelly ³⁵

Anton Koekemoer ^{1, 36}

K. Kohno ^{37, 38}

Vasily Kokorev ¹⁴

Mingyu Li ²⁴

Zihao Li ²⁴

Xiaojing Lin ^{2, 24}

Georgios E Magdis ^{39, 40, 41}

Ashish K. Meena ⁷

A. Niemiec ^{10, 11, 42}

Armin Nabizadeh ⁸

Johan Richard ⁴³

Charles L. Steinhardt ^{41, 44}

Yunjing Wu ²⁴

Yongda Zhu ²

Siwei Zou ^{24, 45}

Show full list: 47 authors

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Center for Frontier Science, Chiba University, Chiba, Japan |

Steward Observatory, University of Arizona, Tucson, USA |

Center for Astrophysics, Harvard & Smithsonian, Cambridge, USA |

⁴

Instituto de Física de Cantabria (CSIC-UC), Santander, Spain |

⁵

Department of Physics, University of California, Berkeley, Berkeley, USA |

⁶

Department of Physics, Graduate School of Science, Chiba University, Chiba, Japan |

⁷

Department of Physics, Ben-Gurion University of the Negev, Be’er-Sheva, Israel |

⁸

Observational Astrophysics, Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden |

⁹

Swedish Collegium for Advanced Study, Uppsala, Sweden |

¹⁰

Centre for Extragalactic Astronomy, Durham University, Durham, UK |

¹¹

Institute for Computational Cosmology, Durham University, Durham, UK |

¹²

Astrophysics Research Centre, University of KwaZulu-Natal, Durban, South Africa |

¹³

School of Mathematics, Statistics & Computer Science, University of KwaZulu-Natal, Durban, South Africa |

¹⁴

Kapteyn Astronomical Institute, University of Groningen, Groningen, the Netherlands |

¹⁵

School of Earth and Space exploration, Arizona State University, Tempe, USA |

¹⁶

Instituto de Astrofísica and Centro de Astroingeniería, Facultad de Física, Pontificia Universidad Católica de Chile, Campus San Joaquín, Macul Santiago, Chile

¹⁷

Millennium Institute of Astrophysics, Providencia, Chile |

¹⁸

Space Science Institute, Boulder, USA |

¹⁹

European Southern Observatory, Vitacura, Chile |

²⁰

European Space Agency (ESA), European Space Astronomy Centre (ESAC), Madrid, Spain |

²¹

Department of Physics, University of the Basque Country, Bilbao, Spain |

²²

Donostia International Physics Centre, San Sebastian, Spain |

²³

Ikerbasque, Basque foundation for Science, Bilbao, Spain |

²⁴

Department of Astronomy, Tsinghua University, Beijing, China |

²⁵

Academia Sinica Institute of Astronomy and Astrophysics (ASIAA), Taipei, Taiwan |

²⁶

Department of Physics, Oklahoma State University, Stillwater, USA |

²⁷

Jodrell Bank Centre for Astrophysics, University of Manchester, Manchester, UK |

²⁸

Departamento de Física Teórica y del Cosmos, Universidad de Granada, Granada, Spain |

²⁹

Instituto Carlos I de Física Teórica y Computacional, Facultad de Ciencias, Granada, Spain |

³⁰

Department of Astronomy/Steward Observatory, University of Arizona, Tucson, USA |

³¹

Department of Astronomy, University of Texas at Austin, Austin, USA |

³²

Center for Astrophysical Sciences, Department of Physics and Astronomy, Johns Hopkins University, Baltimore, USA |

³³

Max-Planck-Institut für extraterrestrische Physik (MPE), Garching, Germany |

³⁴

Department of Physics, University of Tokyo, Tokyo, Japan |

³⁵

Minnesota Institute for Astrophysics, University of Minnesota, Minneapolis, USA |

³⁶

Space Telescope Science Institute, Baltimore, USA |

³⁷

Institute of Astronomy, Graduate School of Science, University of Tokyo, Mitaka, Japan |

³⁸

Research Center for the Early Universe, Graduate School of Science, University of Tokyo, Tokyo, Japan |

³⁹

Cosmic Dawn Center (DAWN), Lyngby, Denmark

⁴⁰

DTU-Space, Technical University of Denmark, Kongens Lyngby, Denmark |

⁴¹

Niels Bohr institute, University of Copenhagen, Copenhagen, Denmark |

⁴²

LPNHE, CNRS/IN2P3, Sorbonne Université, Université Paris-Cité, Laboratoire de Physique Nucléaire et de Hautes Énergies, Paris, France

⁴³

Univ Lyon, Univ Lyon1, Ens de Lyon, CNRS, Centre de Recherche Astrophysique de Lyon, Saint-Genis-Laval, France

⁴⁴

Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark |

⁴⁵

Chinese Academy of Sciences, South America Center for Astronomy, National Astronomical Observatories, CAS, Beijing, China

Publication type: Journal Article

Publication date: 2025-01-06

Springer Nature

Journal: Nature Astronomy

scimago Q1

wos Q1

SJR: 3.311

CiteScore: 19.5

Impact factor: 12.9

ISSN: 23973366

DOI: 10.1038/s41550-024-02432-3

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Abstract

Strong gravitational magnification enables the detection of faint background sources and allows researchers to resolve their internal structures and even identify individual stars in distant galaxies. Highly magnified individual stars are useful in various applications, including studies of stellar populations in distant galaxies and constraining dark matter structures in the lensing plane. However, these applications have been hampered by the small number of individual stars observed, as typically one or a few stars are identified from each distant galaxy. Here, we report the discovery of more than 40 microlensed stars in a single galaxy behind Abell 370 at redshift of 0.725 (dubbed ‘the Dragon arc’) when the Universe was half of its current age, using James Webb Space Telescope observations with the time-domain technique. These events were found near the expected lensing critical curves, suggesting that these are magnified stars that appear as transients from intracluster stellar microlenses. Through multi-wavelength photometry, we constrained their stellar types and found that many of them are consistent with red giants or supergiants magnified by factors of hundreds. This finding reveals a high occurrence of microlensing events in the Dragon arc and demonstrates that time-domain observations by the James Webb Space Telescope could lead to the possibility of conducting statistical studies of high-redshift stars. Using JWST, more than 40 individual stars have been detected in a distant galaxy, dating back to when the Universe was only half of its current age. The stars appear to be red (super)giants that are magnified by factors of hundreds.

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Publisher

Springer Nature

Journal

Nature Astronomy

scimago Q1

wos Q1

SJR

3.311

CiteScore

19.5

Impact factor

12.9

ISSN

23973366 (Electronic)

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