LATED: JWST integral field spectroscopy of a galaxy caught in chemical infancy at $z=4.8$ behind Abell 2744
Year: 2026
Type: preprint
Abstract: When Population III (Pop III) star formation ended remains an open question. LATED-1 is an intrinsically faint (MUV=−16.15) Lyα emitter at z=4.80 revealed by VLT/MUSE behind the lensing cluster Abell 2744 (z=0.308). Before any spectroscopic metallicity constraints, it was identified as an extremely metal-poor or metal-free galaxy candidate from JWST imaging by LATED, our novel photometric selection framework. Here we present serendipitous JWST/NIRSpec PRISM integral-field spectroscopy of this target. The spectrum reveals Lyα, Hβ, and Hα at 7.0, 5.6, and 17.7σ, as well as tentative detections of [O III]λλ4959,5007 at 2.9σ, and yields R3=[OIII]λ5007/Hβ=0.59+0.27−0.21, upholding the earlier LATED photometric prediction of R3<1.54 (2σ limit). The canonical JWST-based strong-line calibration, extrapolated to low metallicity, implies log(O/H)=6.45+0.17−0.19, or Z/Z⊙=0.58+0.28−0.20%, placing LATED-1 among the most metal-poor galaxies known. Its modest magnification (μ=2.80) leaves the intrinsic properties insensitive to the lens model. LATED-1 is therefore a dwarf galaxy caught in the earliest state of chemical enrichment, and a compelling target for testing whether Pop III star formation can persist to z<5. The result demonstrates that photometric selection, especially through the LATED methodology, can reach below one per cent solar metallicity to identify Pop III galaxy candidates for spectroscopic follow-up.
Source: arXiv (Cornell University)
Authors: Li, Mingyu, Maiolino, Roberto, Cai, Zheng, Übler, Hannah, Liu, Boyuan, Duan, Qiao, Bian, Fuyan, Cai, Sijia, D'Eugenio, Francesco, Egami, Eiichi, Emonts, Bjorn H. C., Fan, Xiaohui, Isobe, Yuki, Ivey, Lucy R., Ji, Xihan, Jones, Gareth C., Koller, Maria, Lin, Xiaojing, Lovell, Christopher C., Nakajima, Kimihiko, Ouchi, Masami, Pascalau, Robert G., Prochaska, J. Xavier, Scholtz, Jan, Sun, Fengwu, Tacchella, Sandro, Wu, Yunjing, Yu, Fujiang, Zhang, Zijian
Institutions: University of Cambridge, The University of Tokyo, Chinese Academy of Sciences, European Southern Observatory, National Astronomical Observatories, University of Arizona, Westlake University, Kavli Institute for the Physics and Mathematics of the Universe, The University of Tokyo Institutes for Advanced Study
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7213916278