20.500.12556/RUL-171759 In search of the first stars an ultra-compact and very-low-metallicity Lyα emitter deep within the epoch of reionization We present JWST observations of a gravitationally lensed, extremely metal-poor galaxy at redshift z = 8.203 ± 0.001 from the CANUCS survey. Based on the low oxygen to Balmer line ratios, we infer a gas-phase metallicity of 12 + log(O/H) = 6.85 (1.4% solar), making CANUCS-A370-z8-LAE one of the most metal-poor galaxies known at z > 7. The galaxy has a high Hβ equivalent width of 225 ± 50 Å, small half-light radius of only rhl=38‑19+3 pc, and high star formation rate density of 50–100 M⊙ yr‑1 kpc‑2. The galaxy shows high-equivalent-width Lyα emission with an inferred Lyα escape fraction of 0.21 ± 0.05. The high escape fraction of Lyα is likely due to the compact starbursting nature of the galaxy combined with its location in an overdensity traced by at least two other galaxies spectroscopically confirmed to lie within δz = 0.01 that have helped to reionize the environment. The low metallicity of CANUCS-A370-z8-LAE is best explained by a model where infalling metal-poor gas dilutes the interstellar medium, rather than being a young galaxy forming its first stellar populations. Lyman-alpha galaxies Emission line galaxies reionization metallicity true false true Angleški jezik Angleški jezik Članek v reviji 2025-09-01 16:10:37 2025-09-01 16:10:38 2025-09-02 04:29:58 0000-00-00 00:00:00 2025 0 0 id. 26, 10 str. issue 1 Vol. 988 2025 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 2025-07-01 524.8 1538-4357 10.3847/1538-4357/addf49 247269891 Willott_2025_ApJ_988_26.pdf Willott_2025_ApJ_988_26.pdf 1 B26F90E1D7F7E127200335AAFDE6E19A 049f839f187758cf79fd26c7405cee96498372e338e17f0bc6d9b32f82b9f94a 29769f87-873e-11f0-9328-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=215186 https://iopscience.iop.org/article/10.3847/1538-4357/adbbdc/pdf 1 4cfd9fe8-873d-11f0-9328-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=215185 Fakulteta za matematiko in fiziko 0 0 0