20.500.12556/RUL-166375 Detailed study of stars and gas in a z = 8.3 massive merger with extreme dust conditions We present galaxy MACS0416-Y1 at z$_{spec}$ = 8.312 as observed by the CAnadian NIRISS Unbiased Cluster Survey. MACS0416-Y1 has been shown to have extreme dust properties; thus, we study the physical properties and star formation histories of its resolved components. Overall, we find that MACS0416-Y1 is undergoing a star formation burst in three resolved clumps. The central clump is less massive compared to the other clumps and possibly formed in the merging process of the two larger clumps. Although the star formation history indicates an ongoing star formation burst, this gas-rich galaxy shows comparable star formation efficiency to cosmic noon galaxies. Using NIRSpec prism spectroscopy, we measure metallicity, 12 + log (O/H) = 7.76 ± 0.03, ionization parameter, log U = –2.48 ± 0.03, and electron temperature T$_e$ = 18000 ± 4000 K. The emission line ratios of the galaxy indicate an evolved interstellar medium similar to z ∼ 2 star-forming galaxies. Further, we find possible presence of ionization from an active galactic nucleus (AGN) using emission line diagnostics; however, we do not detect a broad-line component in the Hβ emission line. As this gas-rich galaxy is undergoing a major merger, we hypothesize that the high dust temperature in MACS0416-Y1 is caused by the star formation burst or a possible narrow-line AGN. high-redshift galaxies gravitational lensing reionization active galaxies strong gravitational lensing true false true Angleški jezik Ni določen Članek v reviji 2025-01-09 10:41:27 2025-01-09 10:41:29 2025-11-26 14:55:13 0000-00-00 00:00:00 2024 0 0 9 str. no. 2, art. L36 Vol. 977 2024 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 524.8 2041-8213 10.3847/2041-8213/ad9741 221495555 Harshan_2024_ApJL_977_L36.pdf Harshan_2024_ApJL_977_L36.pdf 1 9D6A5CE71C2925532ADB0A2F260397FF f83675e6b7e15502c1c2d79453c9c5dcc3bec5c4dd78873320ca281db700b994 88feda2b-ce6e-11ef-b232-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=197952 https://iopscience.iop.org/article/10.3847/2041-8213/ad9741 0 3489a4af-cac9-11f0-9328-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=222575 Fakulteta za matematiko in fiziko 0 0 0