{"title":"Catching the nebular needle in a polluted haystack: Line-emission signatures from population III-forming pockets around massive galaxies at the end of reionization","publisher":"IOP Publishing","file":[{"access_level":"open_access","creator":"dernst","file_id":"22375","relation":"main_file","date_created":"2026-07-20T13:05:27Z","file_name":"2026_AstrophysicalJour_Venditti.pdf","date_updated":"2026-07-20T13:05:27Z","content_type":"application/pdf","checksum":"e783c9c10cf773482ac2f3b340ad130b","success":1,"file_size":2267572}],"date_published":"2026-07-10T00:00:00Z","oa_version":"Published Version","acknowledgement":"We thank Elka Rusta and Stefania Salvadori for providing predictions of the He II line luminosities from the NEFERTITI model. A.V. acknowledges funding from the Cosmic Frontier Center and the University of Texas at Austin’s College of Natural Sciences. A.V., L.G., and R.S. acknowledge support from the PRIN 2022 MUR project 2022CB3PJ3—First Light And Galaxy aSsembly (FLAGS) funded by the European Union—Next Generation EU. J.B.M. was supported by NSF Grants AST-2307354 and AST-2408637, and by the NSF-Simons AI Institute for Cosmic Origins. This research was also supported in part by grant NSF PHY-2309135 to the Kavli Institute for Theoretical Physics (KITP). R.V. acknowledges support from PRIN MUR “2022935STW” funded by European Union-Next Generation EU, Missione 4 Componente 2 CUP C53D23000950006 and from Bando Ricerca Fondamentale INAF 2023, Theory Grant “Theoretical models for Black Holes Archaeology.\" C.D.C. acknowledges support from the European Union (ERC, AGENTS, 101076224).","researchdata_availability":"no","_id":"22364","quality_controlled":"1","OA_type":"gold","file_date_updated":"2026-07-20T13:05:27Z","date_created":"2026-07-19T22:01:46Z","arxiv":1,"DOAJ_listed":"1","issue":"2","PlanS_conform":"1","citation":{"short":"A. Venditti, L. Graziani, R. Schneider, V. Bromm, J.B. Muñoz, C. Di Cesare, R. Valiante, A. Calabrò, R. Maiolino, S.L. Finkelstein, M. Parente, M. Saggini, J. Chisholm, The Astrophysical Journal 1005 (2026).","apa":"Venditti, A., Graziani, L., Schneider, R., Bromm, V., Muñoz, J. B., Di Cesare, C., … Chisholm, J. (2026). Catching the nebular needle in a polluted haystack: Line-emission signatures from population III-forming pockets around massive galaxies at the end of reionization. <i>The Astrophysical Journal</i>. IOP Publishing. <a href=\"https://doi.org/10.3847/1538-4357/ae7b2c\">https://doi.org/10.3847/1538-4357/ae7b2c</a>","ista":"Venditti A, Graziani L, Schneider R, Bromm V, Muñoz JB, Di Cesare C, Valiante R, Calabrò A, Maiolino R, Finkelstein SL, Parente M, Saggini M, Chisholm J. 2026. Catching the nebular needle in a polluted haystack: Line-emission signatures from population III-forming pockets around massive galaxies at the end of reionization. The Astrophysical Journal. 1005(2), 226.","ama":"Venditti A, Graziani L, Schneider R, et al. Catching the nebular needle in a polluted haystack: Line-emission signatures from population III-forming pockets around massive galaxies at the end of reionization. <i>The Astrophysical Journal</i>. 2026;1005(2). doi:<a href=\"https://doi.org/10.3847/1538-4357/ae7b2c\">10.3847/1538-4357/ae7b2c</a>","ieee":"A. Venditti <i>et al.</i>, “Catching the nebular needle in a polluted haystack: Line-emission signatures from population III-forming pockets around massive galaxies at the end of reionization,” <i>The Astrophysical Journal</i>, vol. 1005, no. 2. IOP Publishing, 2026.","chicago":"Venditti, Alessandra, Luca Graziani, Raffaella Schneider, Volker Bromm, Julian B. Muñoz, Claudia Di Cesare, Rosa Valiante, et al. “Catching the Nebular Needle in a Polluted Haystack: Line-Emission Signatures from Population III-Forming Pockets around Massive Galaxies at the End of Reionization.” <i>The Astrophysical Journal</i>. IOP Publishing, 2026. <a href=\"https://doi.org/10.3847/1538-4357/ae7b2c\">https://doi.org/10.3847/1538-4357/ae7b2c</a>.","mla":"Venditti, Alessandra, et al. “Catching the Nebular Needle in a Polluted Haystack: Line-Emission Signatures from Population III-Forming Pockets around Massive Galaxies at the End of Reionization.” <i>The Astrophysical Journal</i>, vol. 1005, no. 2, 226, IOP Publishing, 2026, doi:<a href=\"https://doi.org/10.3847/1538-4357/ae7b2c\">10.3847/1538-4357/ae7b2c</a>."},"user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","oa":1,"OA_place":"publisher","scopus_import":"1","date_updated":"2026-07-20T13:07:08Z","supplementarymaterial":"yes","department":[{"_id":"JoMa"}],"project":[{"name":"Young galaxies as tracers and agents of cosmic reionization","grant_number":"101076224","_id":"bd9b2118-d553-11ed-ba76-db24564edfea"}],"status":"public","article_processing_charge":"Yes","publication":"The Astrophysical Journal","external_id":{"arxiv":["2603.27582"]},"article_number":"226","abstract":[{"lang":"eng","text":"Finding the first generation of (Population III or Pop III) stars is one of the most ambitious and exciting challenges of astrophysics. JWST opened concrete prospects for their detection during the Epoch of Reionization, where increasing evidence suggests that residual Pop III formation may persist, even within pristine pockets of high-mass halos, due to inhomogeneous enrichment. However, the identification of Pop III stars within globally enriched environments will be challenging. We investigate the detectability of a subdominant Pop III component in/around massive (M⋆ ≳ 10^9 M⊙) galaxies at z ≈ 6.5–9 from the dustyGadget cosmological simulation suite, and the confusion arising from second-generation (Pop II) stars in their surroundings. We find that young (≲1 Myr), massive (MIII ∼ 6 × 10^5 M⊙) Pop III clusters forming within these galaxy environments are responsible for strong HeII1640 line emission (LHeII1640 ≳ 10^41 erg ^s−1), which would be detectable with ≈10(50) hr of medium-resolution observations with NIRSpec/IFU at z ≈ 6(10). These bright luminosities cannot be produced by standard Pop II populations alone. On the other hand, the dominant Pop II component within massive “hybrid” Pop III hosts powers strong metal line emission (L[OIII]5007 ≳ 10^42 erg s^−1), indicating that the detection of metal lines alone cannot exclude the presence of Pop IIIs in high-z galaxy environments. We further discuss candidate selection strategies based on Lyα, Hα, and Hβ emission, and how spatially resolved observations may enable the detection of isolated, pristine pockets in the outskirts of massive halos."}],"year":"2026","ddc":["520"],"language":[{"iso":"eng"}],"month":"07","doi":"10.3847/1538-4357/ae7b2c","das_tickbox":"1","dataavailabilitystatement":"Software: dustyGadget (L. Graziani et al. 2020), BPASSv2.2.134 (J. J. Eldridge et al. 2017; E. R. Stanway & J. J. Eldridge 2018), Yggdrasil35 (E. Zackrisson et al. 2011), Cloudy22.0136 (G. J. Ferland et al. 2017), NumPy37 (S. van der Walt et al. 2011; C. R. Harris et al. 2020), matplotlib38 (J. D. Hunter 2007), SciPy39 (Jones et al. 2001; P. Virtanen et al. 2020).","article_type":"original","publication_status":"published","has_accepted_license":"1","type":"journal_article","publication_identifier":{"issn":["0004-637X"],"eissn":["1538-4357"]},"tmp":{"legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","short":"CC BY (4.0)","image":"/images/cc_by.png"},"intvolume":"      1005","author":[{"first_name":"Alessandra","full_name":"Venditti, Alessandra","last_name":"Venditti"},{"last_name":"Graziani","full_name":"Graziani, Luca","first_name":"Luca"},{"full_name":"Schneider, Raffaella","last_name":"Schneider","first_name":"Raffaella"},{"first_name":"Volker","full_name":"Bromm, Volker","last_name":"Bromm"},{"first_name":"Julian B.","last_name":"Muñoz","full_name":"Muñoz, Julian B."},{"full_name":"Di Cesare, Claudia","last_name":"Di Cesare","id":"2d002343-372f-11ef-98ec-a164d20427cb","first_name":"Claudia"},{"last_name":"Valiante","full_name":"Valiante, Rosa","first_name":"Rosa"},{"full_name":"Calabrò, Antonello","last_name":"Calabrò","first_name":"Antonello"},{"full_name":"Maiolino, Roberto","last_name":"Maiolino","first_name":"Roberto"},{"first_name":"Steven L.","last_name":"Finkelstein","full_name":"Finkelstein, Steven L."},{"last_name":"Parente","full_name":"Parente, Massimiliano","first_name":"Massimiliano"},{"first_name":"Matteo","full_name":"Saggini, Matteo","last_name":"Saggini"},{"first_name":"John","last_name":"Chisholm","full_name":"Chisholm, John"}],"volume":1005,"day":"10"}