GA-NIFS view of LAP1: Assembly of Pop~III stellar clusters during EoR

J. Scholtz; R. Maiolino; S. Carniani; E. Vanzella; R. J. Terlevich; H. Übler; M. Perna; S. Arribas; E. Bertola; P. Bergamini; T. Böker; A. Bolamperti; A. Bunker; S. Charlot; M. Curti; F. D'Eugenio; C. Grillo; L. R. Ivey; X. Ji; G. C. Jones; M. Meneghetti; M. M. Messa; R. Pascalau; B. Rodríguez Del Pino; P. Rosati; E. Rusta; S. Salvadori; E. Terlevich; G. Venturi; S. Zamora; A. Zanella

arXiv · 2609.35945

GA-NIFS view of LAP1: Assembly of Pop~III stellar clusters during EoR

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Abstract

Lensed and Pristine 1 (LAP1) is one of the most promising candidates for the detection of so-called Pop~III stars at $z\sim6.6$. In this work, we present new high-spectral-resolution ($R \sim 2700$) \jwst NIRSpec-IFS observations of the system along with a detailed re-analysis of all archival \jwst and VLT/MUSE data. We confirm the very low metallicity of the system, with $12+\log(\text{O/H})=6.5\text{--}6.8$ (1--2\% Z$_{\odot}$), and its low stellar mass, with $M_{*}= 10^{3\text{--}4}$ \Msun, based on the non-detection in \jwst/NIRCam filter stacks and the \Hbeta luminosity. The high-resolution IFS data allow us to constrain the upper limits on the dynamical masses ($\log_{10}(M_{*}/M_{\odot})$) of the A and B components to $<6.6\text{--}7.6$ and $<5.6\text{--}6.6$, respectively. Based on the metallicity and the high equivalent width of \Halpha (EW $>1200$\,Å), we estimate the possible range of the LAP1 stellar population ages to be $2\text{--}5$~Myr, consistent with the first burst of star formation in a pristine environment. Based on the size ($<10$~pc) and mass of the system, we discuss the nature of LAP1 as representing the formation of the first stellar clusters in a larger undetected galaxy, similar to other low-metallicity Pop~III candidates in the literature.

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J. Scholtz, R. Maiolino, S. Carniani, E. Vanzella, R. J. Terlevich, H. Übler, M. Perna, S. Arribas, E. Bertola, P. Bergamini, T. Böker, A. Bolamperti, A. Bunker, S. Charlot, M. Curti, F. D'Eugenio, C. Grillo, L. R. Ivey, X. Ji, G. C. Jones, M. Meneghetti, M. M. Messa, R. Pascalau, B. Rodríguez Del Pino, P. Rosati, E. Rusta, S. Salvadori, E. Terlevich, G. Venturi, S. Zamora, A. Zanella. 2026-09-28. GA-NIFS view of LAP1: Assembly of Pop~III stellar clusters during EoR. https://arxiv.org/abs/2609.35945

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