Fudamoto, YoshinobuSun, FengwuDiego, Jose M.Dai, LiangOguri, MasamuneZitrin, AdiZackrisson, ErikJauzac, MathildeLagattuta, David J.Egami, EiichiIani, EdoardoWindhorst, Rogier A.Abe, Katsuya T.Bauer, Franz ErikBian, FuyanBhatawdekar, RachanaBroadhurst, Thomas J.Cai, ZhengChen, Chian-ChouChen, WenleiCohen, Seth H.Conselice, Christopher J.Espada, DanielFoo, NicholasFrye, Brenda L.Fujimoto, SeijiFurtak, Lukas J.Golubchik, MiriamHsiao, Tiger Yu-YangJolly, Jean-BaptisteKawai, HirokiKelly, Patrick L.Koekemoer, Anton M.Kohno, KotaroKokorev, VasilyLi, MingyuLi, ZihaoLin, XiaojingMagdis, Georgios E.Meena, Ashish K.Niemiec, AnnaNabizadeh, ArminRichard, JohanSteinhardt, Charles L.Wu, YunjingZhu, YongdaZou, Siweifudamoto, yoshinobu2025-02-122025-01-06Fudamoto, Yoshinobu, Fengwu Sun, Jose M. Diego, Liang Dai, Masamune Oguri, Adi Zitrin, Erik Zackrisson et al. "Identification of more than 40 gravitationally magnified stars in a galaxy at redshift 0.725." Nat Astron No Volume. DOI: 10.1038/s41550-024-02432-32397-3366https://nrs.harvard.edu/URN-3:HUL.INSTREPOS:37380382Strong gravitational magnifications enable to detect faint background sources, resolve their internal structures, and even identify individual stars in distant galaxies. Highly magnified individual stars allow various appli- cations, including studies of stellar populations in dis- tant 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 be- hind Abell 370 at redshift of 0.725 when the Universe was half of its current age (dubbed “the Dragon arc”), using James Webb Space Telescope (JWST) observations with the time-domain technique. These events are found near the expected lensing critical curves, suggesting that these are magnified stars that appear as transients from intr- acluster stellar microlenses. Through multi-wavelength photometry, we constrain stellar types and find that many of them are consistent with red giants/supergiants magnified by factors of hundreds. This finding reveals an unprecedented high occurrence of microlensing events in the Dragon arc, and proves that JWST’s time-domain observations open up the possibility of conducting statistical studies of high-redshift stars.en-USJournal Article2025-02-1210.1038/s41550-024-02432-3