[{"publication_status":"published","year":"2026","OA_type":"diamond","publisher":"EDP Sciences","PlanS_conform":"1","department":[{"_id":"JoMa"},{"_id":"GradSch"}],"type":"journal_article","external_id":{"arxiv":["2505.09542"]},"day":"14","oa":1,"article_processing_charge":"No","title":"A weak Ly α halo for an extremely bright little red dot. Indications of enshrouded supermassive black hole growth","publication_identifier":{"issn":["0004-6361"],"eissn":["1432-0746"]},"user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","arxiv":1,"article_type":"original","language":[{"iso":"eng"}],"OA_place":"publisher","file_date_updated":"2026-02-16T07:35:03Z","doi":"10.1051/0004-6361/202555596","_id":"21045","scopus_import":"1","oa_version":"Published Version","project":[{"grant_number":"101076224","_id":"bd9b2118-d553-11ed-ba76-db24564edfea","name":"Young galaxies as tracers and agents of cosmic reionization"}],"quality_controlled":"1","date_created":"2026-01-25T23:01:41Z","status":"public","author":[{"first_name":"Alberto","orcid":"0000-0001-5586-6950","last_name":"Torralba Torregrosa","full_name":"Torralba Torregrosa, Alberto","id":"018f0249-0e87-11f0-b167-cbce08fbd541"},{"first_name":"Jorryt J","orcid":"0000-0003-2871-127X","last_name":"Matthee","id":"7439a258-f3c0-11ec-9501-9df22fe06720","full_name":"Matthee, Jorryt J"},{"full_name":"Pezzulli, Gabriele","last_name":"Pezzulli","first_name":"Gabriele"},{"first_name":"Tanya","last_name":"Urrutia","full_name":"Urrutia, Tanya"},{"full_name":"Gronke, Max","first_name":"Max","last_name":"Gronke"},{"last_name":"Mascia","first_name":"Sara","id":"edaf889c-c7cd-11ef-ab1b-bb28c431bd29","full_name":"Mascia, Sara"},{"full_name":"D’Eugenio, Francesco","last_name":"D’Eugenio","first_name":"Francesco"},{"first_name":"Claudia","last_name":"Di Cesare","id":"2d002343-372f-11ef-98ec-a164d20427cb","full_name":"Di Cesare, Claudia"},{"first_name":"Anna Christina","last_name":"Eilers","full_name":"Eilers, Anna Christina"},{"full_name":"Greene, Jenny E.","last_name":"Greene","first_name":"Jenny E."},{"first_name":"Edoardo","orcid":"0000-0001-8386-3546","last_name":"Iani","id":"4053390a-6b68-11ef-9828-a3b8adef8d0a","full_name":"Iani, Edoardo"},{"full_name":"Ishikawa, Yuzo","first_name":"Yuzo","last_name":"Ishikawa"},{"first_name":"Ruari","last_name":"Mackenzie","full_name":"Mackenzie, Ruari"},{"last_name":"Naidu","first_name":"Rohan P.","full_name":"Naidu, Rohan P."},{"full_name":"Navarrete, Benjamín","id":"aa14a535-50c9-11ef-b52e-e0c373d10148","last_name":"Navarrete","first_name":"Benjamín"},{"last_name":"Kotiwale","first_name":"Gauri","id":"1438afc8-1ff6-11ee-9fa6-cd4a75d66875","full_name":"Kotiwale, Gauri"}],"publication":"Astronomy and Astrophysics","acknowledgement":"We thank the anonymous referee for constructive and useful comments. We thank Sebastiano Cantalupo for comments on the draft. Based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere under ESO programme 114.27M6.001. Funded by the European Union (ERC, AGENTS, 101076224). Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Research Council. Neither the European Union nor the granting authority can be held responsible for them. We acknowledge funding from JWST program GO-3516. This work is based in part on observations made with the NASA/ESA/CSA James Webb Space Telescope. The data were obtained from the Mikulski Archive for Space Telescopes at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-03127 for JWST. These observations are associated with program #3516. MG thanks the Max Planck Society for support through the MPRG. FDE acknowledges support by the Science and Technology Facilities Council (STFC), by the ERC through Advanced Grant 695671 “QUENCH”, and by the UKRI Frontier Research grant RISEandFALL. TU acknowledges funding from the ERC-AdG grant SPECMAP-CGM, GA 101020943. GK acknowledges support from the MERAC foundation.","volume":705,"ddc":["520"],"article_number":"A147","month":"01","file":[{"relation":"main_file","checksum":"3782e03bc0843438aae8487f6af779c5","date_updated":"2026-02-16T07:35:03Z","creator":"dernst","access_level":"open_access","date_created":"2026-02-16T07:35:03Z","file_size":2259914,"content_type":"application/pdf","file_name":"2026_AstronomyAstrophysics_Torralba.pdf","success":1,"file_id":"21224"}],"tmp":{"short":"CC BY (4.0)","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","image":"/images/cc_by.png","legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode"},"date_published":"2026-01-14T00:00:00Z","corr_author":"1","has_accepted_license":"1","abstract":[{"text":"The abundant population of little red dots (LRDs), compact objects with red UV to optical colors and broad Balmer lines at high redshift, is revealing new insights into the properties of early active galactic nuclei (AGN). Perhaps the most surprising features of this population are the presence of Balmer absorption and ubiquitous strong Balmer breaks. Recent models link these features to an active supermassive black hole (SMBH) cocooned in very dense gas (NH ∼ 1024 cm−2). We present a stringent test of such models using VLT/MUSE observations of A2744-45924, the most luminous LRD known to date (LHα ≈ 1044 erg s−1), located behind the Abell-2744 lensing cluster at z = 4.464 (μ = 1.8). We detect a moderately extended Lyα nebula (h ≈ 5.7 pkpc), spatially offset from the point-like Hα seen by JWST by ≈1.6 pkpc. The Lyα emission is narrow (FWHM = 270 ± 15 km s−1), and faint (Lyα = 0.07Hα) compared to Lyα nebulae typically observed around quasars of similar luminosity. We detect compact N IV]λ1486 emission, spatially aligned with Hα, and a spatial shift in the far-UV continuum matching the Lyα offset. We discuss that Hα and Lyα have distinct physical origins: Hα originates from the AGN, while Lyα is powered by star formation. In the environment of A2744-45924, we identified four extended Lyα halos (Δz < 0.02, Δr < 100 pkpc). Their Lyα luminosities match the expectations based on Hα emission, and show no evidence for radiation from A2744-45924 affecting its surroundings. The lack of strong, compact, and broad Lyα and the absence of a luminous extended halo, suggest that the UV AGN light is obscured by dense gas cloaking the SMBH with a covering factor close to unity.","lang":"eng"}],"citation":{"ista":"Torralba Torregrosa A, Matthee JJ, Pezzulli G, Urrutia T, Gronke M, Mascia S, D’Eugenio F, Di Cesare C, Eilers AC, Greene JE, Iani E, Ishikawa Y, Mackenzie R, Naidu RP, Navarrete B, Kotiwale G. 2026. A weak Ly α halo for an extremely bright little red dot. Indications of enshrouded supermassive black hole growth. Astronomy and Astrophysics. 705, A147.","ama":"Torralba Torregrosa A, Matthee JJ, Pezzulli G, et al. A weak Ly α halo for an extremely bright little red dot. Indications of enshrouded supermassive black hole growth. <i>Astronomy and Astrophysics</i>. 2026;705. doi:<a href=\"https://doi.org/10.1051/0004-6361/202555596\">10.1051/0004-6361/202555596</a>","chicago":"Torralba Torregrosa, Alberto, Jorryt J Matthee, Gabriele Pezzulli, Tanya Urrutia, Max Gronke, Sara Mascia, Francesco D’Eugenio, et al. “A Weak Ly α Halo for an Extremely Bright Little Red Dot. Indications of Enshrouded Supermassive Black Hole Growth.” <i>Astronomy and Astrophysics</i>. EDP Sciences, 2026. <a href=\"https://doi.org/10.1051/0004-6361/202555596\">https://doi.org/10.1051/0004-6361/202555596</a>.","ieee":"A. Torralba Torregrosa <i>et al.</i>, “A weak Ly α halo for an extremely bright little red dot. Indications of enshrouded supermassive black hole growth,” <i>Astronomy and Astrophysics</i>, vol. 705. EDP Sciences, 2026.","mla":"Torralba Torregrosa, Alberto, et al. “A Weak Ly α Halo for an Extremely Bright Little Red Dot. Indications of Enshrouded Supermassive Black Hole Growth.” <i>Astronomy and Astrophysics</i>, vol. 705, A147, EDP Sciences, 2026, doi:<a href=\"https://doi.org/10.1051/0004-6361/202555596\">10.1051/0004-6361/202555596</a>.","short":"A. Torralba Torregrosa, J.J. Matthee, G. Pezzulli, T. Urrutia, M. Gronke, S. Mascia, F. D’Eugenio, C. Di Cesare, A.C. Eilers, J.E. Greene, E. Iani, Y. Ishikawa, R. Mackenzie, R.P. Naidu, B. Navarrete, G. Kotiwale, Astronomy and Astrophysics 705 (2026).","apa":"Torralba Torregrosa, A., Matthee, J. J., Pezzulli, G., Urrutia, T., Gronke, M., Mascia, S., … Kotiwale, G. (2026). A weak Ly α halo for an extremely bright little red dot. Indications of enshrouded supermassive black hole growth. <i>Astronomy and Astrophysics</i>. EDP Sciences. <a href=\"https://doi.org/10.1051/0004-6361/202555596\">https://doi.org/10.1051/0004-6361/202555596</a>"},"intvolume":"       705","date_updated":"2026-02-16T07:46:53Z"},{"intvolume":"       706","date_updated":"2026-02-24T07:49:42Z","date_published":"2026-02-01T00:00:00Z","tmp":{"short":"CC BY (4.0)","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","image":"/images/cc_by.png","legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode"},"abstract":[{"lang":"eng","text":"We aim to characterise the mass-metallicity relation (MZR) and the 3D correlation between the stellar mass, metallicity, and star formation rate (SFR) known as the fundamental metallicity relation (FMR) for galaxies at 5 < z < 7. Using ∼800 [O III] selected galaxies from deep NIRCam grism surveys, we present our stacked measurements of direct-Te metallicities, which we used to test recent strong-line metallicity calibrations. Our measured direct-Te metallicities (0.1–0.2 Z⊙ for M★ ≈ 5 × 107 − 9 M⊙, respectively) match recent JWST/NIRSpec-based results. However, there are significant inconsistencies between observations and hydrodynamical simulations. We observe a flatter MZR slope than the SPHINX20 and FLARES simulations, which cannot be attributed to selection effects. With simple models, we show that the effect of an [O III] flux-limited sample on the observed shape of the MZR is strongly dependent on the FMR. If the FMR is similar to the one in the local Universe, the intrinsic high-redshift MZR should be even flatter than is observed. In turn, a 3D relation where SFR correlates positively with metallicity at fixed mass would imply an intrinsically steeper MZR. Our measurements indicate that metallicity variations at fixed mass show little dependence on the SFR, suggesting a flat intrinsic MZR. This could indicate that the low-mass galaxies at these redshifts are out of equilibrium and that metal enrichment occurs rapidly in low-mass galaxies. However, being limited by our stacking analysis, we are yet to probe the scatter in the MZR and its dependence on SFR. Large carefully selected samples of galaxies with robust metallicity measurements can put tight constraints on the high-redshift FMR and help us to understand the interplay between gas flows, star formation, and feedback in early galaxies."}],"citation":{"ista":"Kotiwale G, Matthee JJ, Kashino D, Vijayan AP, Torralba Torregrosa A, Di Cesare C, Iani E, Bordoloi R, Leja J, Maseda MV, Tacchella S, Shivaei I, Heintz KE, Danhaive AL, Mascia S, Kramarenko I, Navarrete B, Mackenzie R, Naidu RP, Sobral D. 2026. Rapid, out-of-equilibrium metal enrichment indicated by a flat mass-metallicity relation at z ∼ 6 from NIRCam grism spectroscopy. Astronomy &#38; Astrophysics. 706, A165.","ieee":"G. Kotiwale <i>et al.</i>, “Rapid, out-of-equilibrium metal enrichment indicated by a flat mass-metallicity relation at z ∼ 6 from NIRCam grism spectroscopy,” <i>Astronomy &#38; Astrophysics</i>, vol. 706. EDP Sciences, 2026.","short":"G. Kotiwale, J.J. Matthee, D. Kashino, A.P. Vijayan, A. Torralba Torregrosa, C. Di Cesare, E. Iani, R. Bordoloi, J. Leja, M.V. Maseda, S. Tacchella, I. Shivaei, K.E. Heintz, A.L. Danhaive, S. Mascia, I. Kramarenko, B. Navarrete, R. Mackenzie, R.P. Naidu, D. Sobral, Astronomy &#38; Astrophysics 706 (2026).","mla":"Kotiwale, Gauri, et al. “Rapid, out-of-Equilibrium Metal Enrichment Indicated by a Flat Mass-Metallicity Relation at z ∼ 6 from NIRCam Grism Spectroscopy.” <i>Astronomy &#38; Astrophysics</i>, vol. 706, A165, EDP Sciences, 2026, doi:<a href=\"https://doi.org/10.1051/0004-6361/202556597\">10.1051/0004-6361/202556597</a>.","apa":"Kotiwale, G., Matthee, J. J., Kashino, D., Vijayan, A. P., Torralba Torregrosa, A., Di Cesare, C., … Sobral, D. (2026). Rapid, out-of-equilibrium metal enrichment indicated by a flat mass-metallicity relation at z ∼ 6 from NIRCam grism spectroscopy. <i>Astronomy &#38; Astrophysics</i>. EDP Sciences. <a href=\"https://doi.org/10.1051/0004-6361/202556597\">https://doi.org/10.1051/0004-6361/202556597</a>","ama":"Kotiwale G, Matthee JJ, Kashino D, et al. Rapid, out-of-equilibrium metal enrichment indicated by a flat mass-metallicity relation at z ∼ 6 from NIRCam grism spectroscopy. <i>Astronomy &#38; Astrophysics</i>. 2026;706. doi:<a href=\"https://doi.org/10.1051/0004-6361/202556597\">10.1051/0004-6361/202556597</a>","chicago":"Kotiwale, Gauri, Jorryt J Matthee, Daichi Kashino, Aswin P. Vijayan, Alberto Torralba Torregrosa, Claudia Di Cesare, Edoardo Iani, et al. “Rapid, out-of-Equilibrium Metal Enrichment Indicated by a Flat Mass-Metallicity Relation at z ∼ 6 from NIRCam Grism Spectroscopy.” <i>Astronomy &#38; Astrophysics</i>. EDP Sciences, 2026. <a href=\"https://doi.org/10.1051/0004-6361/202556597\">https://doi.org/10.1051/0004-6361/202556597</a>."},"has_accepted_license":"1","corr_author":"1","month":"02","volume":706,"acknowledgement":"We thank the anonymous referee for the insightful comments that helped improving this paper. This work is based on observations made with the NASA/ESA/CSA James Webb Space Telescope. The data were obtained from the Mikulski Archive for Space Telescopes at the Space Telescope Science Institute, which is operated by the Associations of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-03127 for JWST. These observations were taken under programmes # 1243, # 1933 and # 3516. Funded by the European Union (ERC, AGENTS, 101076224). Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Research Council. Neither the European Union nor the granting authority can be held responsible for them. GK acknowledges support from the Foundation MERAC. APV acknowledge support from the Sussex Astronomy Centre STFC Consolidated Grant (ST/X001040/1).","article_number":"A165","ddc":["520"],"file":[{"success":1,"file_name":"2026_AstronomyAstrophysics_Kotiwale.pdf","file_id":"21355","file_size":6531719,"content_type":"application/pdf","creator":"dernst","date_updated":"2026-02-24T07:46:47Z","date_created":"2026-02-24T07:46:47Z","access_level":"open_access","relation":"main_file","checksum":"6f5849d29ad43bee32f90152f6fc0294"}],"status":"public","author":[{"last_name":"Kotiwale","first_name":"Gauri","id":"1438afc8-1ff6-11ee-9fa6-cd4a75d66875","full_name":"Kotiwale, Gauri"},{"first_name":"Jorryt J","last_name":"Matthee","orcid":"0000-0003-2871-127X","id":"7439a258-f3c0-11ec-9501-9df22fe06720","full_name":"Matthee, Jorryt J"},{"full_name":"Kashino, Daichi","first_name":"Daichi","last_name":"Kashino"},{"last_name":"Vijayan","first_name":"Aswin P.","full_name":"Vijayan, Aswin P."},{"first_name":"Alberto","last_name":"Torralba Torregrosa","orcid":"0000-0001-5586-6950","full_name":"Torralba Torregrosa, Alberto","id":"018f0249-0e87-11f0-b167-cbce08fbd541"},{"first_name":"Claudia","last_name":"Di Cesare","id":"2d002343-372f-11ef-98ec-a164d20427cb","full_name":"Di Cesare, Claudia"},{"id":"4053390a-6b68-11ef-9828-a3b8adef8d0a","full_name":"Iani, Edoardo","orcid":"0000-0001-8386-3546","last_name":"Iani","first_name":"Edoardo"},{"full_name":"Bordoloi, Rongmon","first_name":"Rongmon","last_name":"Bordoloi"},{"full_name":"Leja, Joel","first_name":"Joel","last_name":"Leja"},{"last_name":"Maseda","first_name":"Michael V.","full_name":"Maseda, Michael V."},{"last_name":"Tacchella","first_name":"Sandro","full_name":"Tacchella, Sandro"},{"last_name":"Shivaei","first_name":"Irene","full_name":"Shivaei, Irene"},{"last_name":"Heintz","first_name":"Kasper E.","full_name":"Heintz, Kasper E."},{"last_name":"Danhaive","first_name":"A. Lola","full_name":"Danhaive, A. Lola"},{"last_name":"Mascia","first_name":"Sara","full_name":"Mascia, Sara","id":"edaf889c-c7cd-11ef-ab1b-bb28c431bd29"},{"last_name":"Kramarenko","orcid":"0000-0001-5346-6048","first_name":"Ivan","full_name":"Kramarenko, Ivan","id":"9a9394cb-3200-11ee-973b-f5ba2a8b16e4"},{"full_name":"Navarrete, Benjamín","id":"aa14a535-50c9-11ef-b52e-e0c373d10148","last_name":"Navarrete","first_name":"Benjamín"},{"full_name":"Mackenzie, Ruari","first_name":"Ruari","last_name":"Mackenzie"},{"full_name":"Naidu, Rohan P.","last_name":"Naidu","first_name":"Rohan P."},{"last_name":"Sobral","first_name":"David","full_name":"Sobral, David"}],"publication":"Astronomy & Astrophysics","quality_controlled":"1","project":[{"name":"Young galaxies as tracers and agents of cosmic reionization","_id":"bd9b2118-d553-11ed-ba76-db24564edfea","grant_number":"101076224"}],"date_created":"2026-02-22T23:01:35Z","file_date_updated":"2026-02-24T07:46:47Z","language":[{"iso":"eng"}],"OA_place":"publisher","DOAJ_listed":"1","article_type":"original","_id":"21341","oa_version":"Published Version","scopus_import":"1","doi":"10.1051/0004-6361/202556597","article_processing_charge":"No","title":"Rapid, out-of-equilibrium metal enrichment indicated by a flat mass-metallicity relation at z ∼ 6 from NIRCam grism spectroscopy","arxiv":1,"publication_identifier":{"eissn":["1432-0746"],"issn":["0004-6361"]},"user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","PlanS_conform":"1","department":[{"_id":"JoMa"},{"_id":"GradSch"}],"OA_type":"diamond","year":"2026","publication_status":"published","publisher":"EDP Sciences","day":"01","external_id":{"arxiv":["2510.19959"]},"oa":1,"type":"journal_article"},{"date_created":"2026-03-02T10:06:10Z","quality_controlled":"1","doi":"10.1051/0004-6361/202557358","scopus_import":"1","oa_version":"Published Version","_id":"21380","article_type":"original","DOAJ_listed":"1","file_date_updated":"2026-03-02T14:51:57Z","OA_place":"publisher","language":[{"iso":"eng"}],"user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","publication_identifier":{"issn":["0004-6361"],"eissn":["1432-0746"]},"arxiv":1,"title":"J-PAS: First identification, physical properties, and ionization efficiency of extreme emission line galaxies","article_processing_charge":"No","type":"journal_article","oa":1,"external_id":{"arxiv":["2512.08484"]},"day":"01","publisher":"EDP Sciences","year":"2026","publication_status":"published","OA_type":"diamond","department":[{"_id":"JoMa"}],"date_updated":"2026-03-02T15:10:27Z","intvolume":"       706","has_accepted_license":"1","citation":{"chicago":"Giménez-Alcázar, A., R. Amorín, J. M. Vílchez, A. Hernán-Caballero, M. González-Otero, A. Arroyo-Polonio, J. Iglesias-Páramo, et al. “J-PAS: First Identification, Physical Properties, and Ionization Efficiency of Extreme Emission Line Galaxies.” <i>Astronomy &#38; Astrophysics</i>. EDP Sciences, 2026. <a href=\"https://doi.org/10.1051/0004-6361/202557358\">https://doi.org/10.1051/0004-6361/202557358</a>.","ama":"Giménez-Alcázar A, Amorín R, Vílchez JM, et al. J-PAS: First identification, physical properties, and ionization efficiency of extreme emission line galaxies. <i>Astronomy &#38; Astrophysics</i>. 2026;706. doi:<a href=\"https://doi.org/10.1051/0004-6361/202557358\">10.1051/0004-6361/202557358</a>","apa":"Giménez-Alcázar, A., Amorín, R., Vílchez, J. M., Hernán-Caballero, A., González-Otero, M., Arroyo-Polonio, A., … Vázquez Ramió, H. (2026). J-PAS: First identification, physical properties, and ionization efficiency of extreme emission line galaxies. <i>Astronomy &#38; Astrophysics</i>. EDP Sciences. <a href=\"https://doi.org/10.1051/0004-6361/202557358\">https://doi.org/10.1051/0004-6361/202557358</a>","ieee":"A. Giménez-Alcázar <i>et al.</i>, “J-PAS: First identification, physical properties, and ionization efficiency of extreme emission line galaxies,” <i>Astronomy &#38; Astrophysics</i>, vol. 706. EDP Sciences, 2026.","short":"A. Giménez-Alcázar, R. Amorín, J.M. Vílchez, A. Hernán-Caballero, M. González-Otero, A. Arroyo-Polonio, J. Iglesias-Páramo, A. Lumbreras-Calle, J.A. Fernández-Ontiveros, C. López-Sanjuan, L. Bonatto, R.M. González Delgado, C. Kehrig, A. Torralba Torregrosa, P.T. Rahna, Y. Jiménez-Teja, I. Márquez, I. Breda, A. Álvarez-Candal, R. Abramo, J. Alcaniz, N. Benitez, S. Bonoli, S. Carneiro, J. Cenarro, D. Cristóbal-Hornillos, R. Dupke, A. Ederoclite, C. Hernández-Monteagudo, A. Marín-Franch, C. Mendes de Oliveira, M. Moles, L. Sodré, K. Taylor, J. Varela, H. Vázquez Ramió, Astronomy &#38; Astrophysics 706 (2026).","mla":"Giménez-Alcázar, A., et al. “J-PAS: First Identification, Physical Properties, and Ionization Efficiency of Extreme Emission Line Galaxies.” <i>Astronomy &#38; Astrophysics</i>, vol. 706, A261, EDP Sciences, 2026, doi:<a href=\"https://doi.org/10.1051/0004-6361/202557358\">10.1051/0004-6361/202557358</a>.","ista":"Giménez-Alcázar A, Amorín R, Vílchez JM, Hernán-Caballero A, González-Otero M, Arroyo-Polonio A, Iglesias-Páramo J, Lumbreras-Calle A, Fernández-Ontiveros JA, López-Sanjuan C, Bonatto L, González Delgado RM, Kehrig C, Torralba Torregrosa A, Rahna PT, Jiménez-Teja Y, Márquez I, Breda I, Álvarez-Candal A, Abramo R, Alcaniz J, Benitez N, Bonoli S, Carneiro S, Cenarro J, Cristóbal-Hornillos D, Dupke R, Ederoclite A, Hernández-Monteagudo C, Marín-Franch A, Mendes de Oliveira C, Moles M, Sodré L, Taylor K, Varela J, Vázquez Ramió H. 2026. J-PAS: First identification, physical properties, and ionization efficiency of extreme emission line galaxies. Astronomy &#38; Astrophysics. 706, A261."},"abstract":[{"text":"Context. Extreme emission line galaxies (EELGs) are believed to significantly contribute to the star formation activity and mass assembly in galaxies. EELGs likely also play a leading role in the cosmic re-ionization as their interstellar medium may allow a significant fraction of their ionizing photons to escape (> 5%). Finding low-redshift analogues of these high-z galaxies is therefore essential to characterizing the physical conditions in the interstellar medium of these galaxies and understanding the processes that re-ionized the Universe.\r\n\r\nAims. We aimed to develop a robust and efficient method for the photometric identification of EELGs using the J-PAS survey. J-PAS will cover approximately 8500 deg2 of the sky with 54 narrow-band filters in the optical range plus i-SDSS, enabling detailed studies of the physical properties of these galaxies. In this work we focused on an initial subset of the survey: a 30 square degree area with complete observations in all bands.\r\n\r\nMethods. We combine equivalent width (EW) measurements from J-PAS narrow-band photometry with artificial intelligence techniques to identify galaxies with emission lines exceeding 300 Å. We validated our selection using spectroscopic data from DESI DR1 and characterized the selected sample through spectral energy distribution fitting with CIGALE.\r\n\r\nResults. We identify 917 EELGs up to z = 0.8 over 30 deg2, achieving a purity of 95% and a completeness of 96% for i-SDSS < 22.5 mag. Importantly, active galactic nucleus contamination was carefully considered and is estimated to be around 5%. Furthermore, a cross-match with DESI yielded 79 counterparts; their redshifts are in excellent agreement with our photometric estimates, thereby confirming the reliability of our redshift determination. In addition, the derived emission line fluxes are in good agreement with spectroscopic measurements. Moreover, the selected sample reveals strong correlations between the ionizing photon production efficiency (ξion) and EW(Hβ), which are consistent with previous observational studies at low and high redshifts and theoretical expectations. Finally, most of the sources surpass the ionizing efficiency threshold required for re-ionization, highlighting their relevance as local analogues of early-Universe galaxies.","lang":"eng"}],"tmp":{"short":"CC BY (4.0)","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","image":"/images/cc_by.png","legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode"},"date_published":"2026-02-01T00:00:00Z","file":[{"date_created":"2026-03-02T14:51:57Z","access_level":"open_access","creator":"dernst","date_updated":"2026-03-02T14:51:57Z","checksum":"cd25a05386ab5638ae5baf8add0ecbee","relation":"main_file","file_id":"21391","success":1,"file_name":"2026_AstronomyAstrophysics_GimenezAlcazar.pdf","content_type":"application/pdf","file_size":1813456}],"ddc":["520"],"article_number":"A261","acknowledgement":"We thank the referee for several helpful suggestions. AGA, MGO and IM acknowledge financial support from the Severo Ochoa grant CEX2021-001131-S, funded by MICIU/AEI/10.13039/501100011033. AGA also acknowledges FPI support under grant code CEX2021-001131-S20-7. Both AGA and MGO acknowledge support from the research grant\r\nPID2022-136598NB-C32 (“Estallidos8”). MGO also acknowledges the support by the project ref. AST22_00001_Subp_11 funded from the EU – NextGenerationEU. RA acknowledges support from PID2023-147386NB-I00 funded by MICIU/AEI/10.13039/501100011033 and ERDF/EU. IM acknowledges support from PID2022-140871NB-C21 funded by MICIU/AEI/10.13039/501100011033 and FEDER/UE. RGD acknowledge financial support from the project PID2022-141755NB-I00, and the Severo Ochoa grant CEX2021-001131-S funded\r\nby MICIU/AEI/ 10.13039/501100011033. JAFO and AE acknowledge support from the Spanish Ministry of Science and Innovation and the EU–NextGenerationEU through the RRF project ICTS-MRR-2021-03-CEFCA. AHC and ALC acknowledge support from MCIN/AEI/10.13039/501100011033, “ERDF A way of making Europe”, and “EU NextGenerationEU/PRTR” through PID2021-124918NB-C44 and CNS2023-145339, as well as from the RRF project ICTS-MRR-2021-03-CEFCA ALC and RPT acknowledge the financial\r\nsupport from the European Union – NextGenerationEU through the RRF program Planes Complementarios con las CCAA de Astrofísica y Física de Altas Energías – LA4. I.B. acknowledges support from the EU Horizon 2020 programme (Marie Sklodowska-Curie Grant 101059532) and the Franziska Seidl Funding Program, University of Vienna. This paper has gone through internal‘ review by the J-PAS collaboration. Based on observations made with the\r\nJST/T250 telescope and JPCam at the Observatorio Astrofísico de Javalambre (OAJ), in Teruel, owned, managed, and operated by the Centro de Estudios de Física del Cosmos de Aragón (CEFCA). We acknowledge the OAJ Data Processing and Archiving Unit (UPAD) for reducing and calibrating the OAJ data used in this work. Funding for the J-PAS Project has been provided by the Governments of Spain and Aragón through the Fondo de Inversiones de Teruel; the Aragonese Government through the Research Groups E96, E103, E16_17R, E16_20R, and E16_23R; the Spanish Ministry of Science and Innovation (MCIN/AEI/10.13039/501100011033 y FEDER, Una manera de hacer Europa) with grants PID2021-124918NB-C41, PID2021-124918NB-C42, PID2021-124918NA-C43, and PID2021-124918NB-C44; the Spanish Ministry\r\nof Science, Innovation and Universities (MCIU/AEI/FEDER, UE) with grants\r\nPGC2018-097585-B-C21 and PGC2018-097585-B-C22; the Spanish Ministry of Economy and Competitiveness (MINECO) under AYA2015-66211-C2-1-P, AYA2015-66211-C2-2, and AYA2012-30789; and European FEDER funding (FCDD10-4E-867, FCDD13-4E-2685).","volume":706,"month":"02","publication":"Astronomy & Astrophysics","author":[{"last_name":"Giménez-Alcázar","first_name":"A.","full_name":"Giménez-Alcázar, A."},{"first_name":"R.","last_name":"Amorín","full_name":"Amorín, R."},{"full_name":"Vílchez, J. M.","first_name":"J. M.","last_name":"Vílchez"},{"full_name":"Hernán-Caballero, A.","first_name":"A.","last_name":"Hernán-Caballero"},{"first_name":"M.","last_name":"González-Otero","full_name":"González-Otero, M."},{"full_name":"Arroyo-Polonio, A.","last_name":"Arroyo-Polonio","first_name":"A."},{"full_name":"Iglesias-Páramo, J.","first_name":"J.","last_name":"Iglesias-Páramo"},{"last_name":"Lumbreras-Calle","first_name":"A.","full_name":"Lumbreras-Calle, A."},{"full_name":"Fernández-Ontiveros, J. A.","first_name":"J. A.","last_name":"Fernández-Ontiveros"},{"full_name":"López-Sanjuan, C.","first_name":"C.","last_name":"López-Sanjuan"},{"full_name":"Bonatto, L.","first_name":"L.","last_name":"Bonatto"},{"last_name":"González Delgado","first_name":"R. M.","full_name":"González Delgado, R. M."},{"full_name":"Kehrig, C.","first_name":"C.","last_name":"Kehrig"},{"first_name":"Alberto","last_name":"Torralba Torregrosa","orcid":"0000-0001-5586-6950","id":"018f0249-0e87-11f0-b167-cbce08fbd541","full_name":"Torralba Torregrosa, Alberto"},{"full_name":"Rahna, P. T.","last_name":"Rahna","first_name":"P. T."},{"full_name":"Jiménez-Teja, Y.","first_name":"Y.","last_name":"Jiménez-Teja"},{"first_name":"I.","last_name":"Márquez","full_name":"Márquez, I."},{"full_name":"Breda, I.","first_name":"I.","last_name":"Breda"},{"first_name":"A.","last_name":"Álvarez-Candal","full_name":"Álvarez-Candal, A."},{"full_name":"Abramo, R.","first_name":"R.","last_name":"Abramo"},{"first_name":"J.","last_name":"Alcaniz","full_name":"Alcaniz, J."},{"full_name":"Benitez, N.","first_name":"N.","last_name":"Benitez"},{"last_name":"Bonoli","first_name":"S.","full_name":"Bonoli, S."},{"full_name":"Carneiro, S.","last_name":"Carneiro","first_name":"S."},{"first_name":"J.","last_name":"Cenarro","full_name":"Cenarro, J."},{"full_name":"Cristóbal-Hornillos, D.","last_name":"Cristóbal-Hornillos","first_name":"D."},{"full_name":"Dupke, R.","first_name":"R.","last_name":"Dupke"},{"first_name":"A.","last_name":"Ederoclite","full_name":"Ederoclite, A."},{"full_name":"Hernández-Monteagudo, C.","first_name":"C.","last_name":"Hernández-Monteagudo"},{"first_name":"A.","last_name":"Marín-Franch","full_name":"Marín-Franch, A."},{"full_name":"Mendes de Oliveira, C.","last_name":"Mendes de Oliveira","first_name":"C."},{"full_name":"Moles, M.","first_name":"M.","last_name":"Moles"},{"first_name":"L.","last_name":"Sodré","full_name":"Sodré, L."},{"last_name":"Taylor","first_name":"K.","full_name":"Taylor, K."},{"full_name":"Varela, J.","first_name":"J.","last_name":"Varela"},{"full_name":"Vázquez Ramió, H.","last_name":"Vázquez Ramió","first_name":"H."}],"status":"public"},{"article_processing_charge":"No","title":"The warm outer layer of a little red dot as the source of [Fe ii] and collisional Balmer lines with scattering wings","publication_identifier":{"eissn":["1432-0746"],"issn":["0004-6361"]},"user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","arxiv":1,"publication_status":"published","year":"2026","OA_type":"diamond","publisher":"EDP Sciences","department":[{"_id":"JoMa"}],"PlanS_conform":"1","type":"journal_article","external_id":{"arxiv":["2510.00103"]},"day":"01","oa":1,"project":[{"grant_number":"101076224","name":"Young galaxies as tracers and agents of cosmic reionization","_id":"bd9b2118-d553-11ed-ba76-db24564edfea"}],"quality_controlled":"1","date_created":"2026-03-15T23:01:36Z","DOAJ_listed":"1","article_type":"original","file_date_updated":"2026-03-16T10:57:49Z","language":[{"iso":"eng"}],"OA_place":"publisher","doi":"10.1051/0004-6361/202557537","_id":"21451","scopus_import":"1","oa_version":"Published Version","acknowledgement":"We thank the scientific referee for useful and constructive comments. We thank Ylva Götberg and Zoltan Haiman for insightful discussions about the physics of gaseous envelopes and accretion into black holes. Funded by the European Union (ERC, AGENTS, 101076224). Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Research Council. Neither the European Union nor the granting authority can be held responsible for them. This work is based in part on observations made with the NASA/ESA/CSA James Webb Space Telescope. The data were obtained from the Mikulski Archive for Space Telescopes at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-03127 for JWST. These observations are associated with program #5664. This work has received funding from the Swiss State Secretariat for Education, Research and Innovation (SERI) under contract number MB22.00072, as well as from the Swiss National Science Foundation (SNSF) through project grant 200020_207349.","volume":707,"article_number":"A75","ddc":["520"],"month":"03","file":[{"file_id":"21460","file_name":"2026_AstronomyAstrophysics_Torralba2.pdf","success":1,"content_type":"application/pdf","file_size":2510157,"date_created":"2026-03-16T10:57:49Z","access_level":"open_access","date_updated":"2026-03-16T10:57:49Z","creator":"dernst","checksum":"fcab9cb3dcf1d68612e1fdc8191643c1","relation":"main_file"}],"status":"public","author":[{"first_name":"Alberto","orcid":"0000-0001-5586-6950","last_name":"Torralba Torregrosa","full_name":"Torralba Torregrosa, Alberto","id":"018f0249-0e87-11f0-b167-cbce08fbd541"},{"first_name":"Jorryt J","last_name":"Matthee","orcid":"0000-0003-2871-127X","id":"7439a258-f3c0-11ec-9501-9df22fe06720","full_name":"Matthee, Jorryt J"},{"last_name":"Pezzulli","first_name":"Gabriele","full_name":"Pezzulli, Gabriele"},{"full_name":"Naidu, Rohan P.","first_name":"Rohan P.","last_name":"Naidu"},{"full_name":"Ishikawa, Yuzo","last_name":"Ishikawa","first_name":"Yuzo"},{"full_name":"Brammer, Gabriel B.","last_name":"Brammer","first_name":"Gabriel B."},{"full_name":"Chang, Seok Jun","last_name":"Chang","first_name":"Seok Jun"},{"full_name":"Chisholm, John","last_name":"Chisholm","first_name":"John"},{"first_name":"Anna","last_name":"De Graaff","full_name":"De Graaff, Anna"},{"full_name":"D’Eugenio, Francesco","last_name":"D’Eugenio","first_name":"Francesco"},{"last_name":"Di Cesare","first_name":"Claudia","id":"2d002343-372f-11ef-98ec-a164d20427cb","full_name":"Di Cesare, Claudia"},{"first_name":"Anna Christina","last_name":"Eilers","full_name":"Eilers, Anna Christina"},{"full_name":"Greene, Jenny E.","first_name":"Jenny E.","last_name":"Greene"},{"full_name":"Gronke, Max","last_name":"Gronke","first_name":"Max"},{"first_name":"Edoardo","last_name":"Iani","orcid":"0000-0001-8386-3546","id":"4053390a-6b68-11ef-9828-a3b8adef8d0a","full_name":"Iani, Edoardo"},{"full_name":"Kokorev, Vasily","last_name":"Kokorev","first_name":"Vasily"},{"id":"1438afc8-1ff6-11ee-9fa6-cd4a75d66875","full_name":"Kotiwale, Gauri","first_name":"Gauri","last_name":"Kotiwale"},{"first_name":"Ivan","orcid":"0000-0001-5346-6048","last_name":"Kramarenko","full_name":"Kramarenko, Ivan","id":"9a9394cb-3200-11ee-973b-f5ba2a8b16e4"},{"first_name":"Yilun","last_name":"Ma","full_name":"Ma, Yilun"},{"first_name":"Sara","last_name":"Mascia","id":"edaf889c-c7cd-11ef-ab1b-bb28c431bd29","full_name":"Mascia, Sara"},{"first_name":"Benjamín","last_name":"Navarrete","id":"aa14a535-50c9-11ef-b52e-e0c373d10148","full_name":"Navarrete, Benjamín"},{"full_name":"Nelson, Erica","last_name":"Nelson","first_name":"Erica"},{"full_name":"Oesch, Pascal","last_name":"Oesch","first_name":"Pascal"},{"full_name":"Simcoe, Robert A.","last_name":"Simcoe","first_name":"Robert A."},{"first_name":"Stijn","last_name":"Wuyts","full_name":"Wuyts, Stijn"}],"publication":"Astronomy & Astrophysics","intvolume":"       707","date_updated":"2026-03-16T10:59:16Z","tmp":{"short":"CC BY (4.0)","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","image":"/images/cc_by.png","legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode"},"date_published":"2026-03-01T00:00:00Z","has_accepted_license":"1","corr_author":"1","abstract":[{"text":"The population of the little red dots (LRDs) may represent a key phase of supermassive black hole (SMBH) growth. A cocoon of dense excited gas is emerging as a key component to explain the most striking properties of LRDs, such as strong Balmer breaks and Balmer absorption, as well as the weak IR emission. To dissect the structure of LRDs, we analyzed new deep JWST/NIRSpec PRISM and G395H spectra of FRESCO-GN-9771, one of the most luminous known LRDs at z = 5.5. These spectra reveal a strong Balmer break, broad Balmer lines, and very narrow [O III] emission. We revealed a forest of optical [Fe II] lines, which we argue are emerging from a dense (nH = 109 − 10 cm−3) warm layer with electron temperature Te ≈ 7000 K. The broad wings of Hα and Hβ have an exponential profile due to electron scattering in this same layer. The high Hα : Hβ : Hγ flux ratio of ≈10.4 : 1 : 0.14 is an indicator of collisional excitation and resonant scattering dominating the Balmer line emission. A narrow Hγ component, unseen in the other two Balmer lines due to outshining by the broad components, could trace the ISM of a normal host galaxy with a star formation rate of ∼5 M⊙ yr−1. The warm layer is mostly opaque to Balmer transitions, producing a characteristic P Cygni profile in the line centers suggesting outflowing motions. This same layer is responsible for shaping the Balmer break. The broadband spectrum can be reasonably matched by a simple photoionized slab model that dominates the λ > 1500 Å continuum and a low-mass (∼108 M⊙) galaxy that could explain the narrow [O III], with only a subdominant contribution to the UV continuum. Our findings indicate that Balmer lines are not directly tracing the gas kinematics near the SMBH and that the BH mass scale is likely much lower than virial indicators suggest.","lang":"eng"}],"citation":{"ista":"Torralba Torregrosa A, Matthee JJ, Pezzulli G, Naidu RP, Ishikawa Y, Brammer GB, Chang SJ, Chisholm J, De Graaff A, D’Eugenio F, Di Cesare C, Eilers AC, Greene JE, Gronke M, Iani E, Kokorev V, Kotiwale G, Kramarenko I, Ma Y, Mascia S, Navarrete B, Nelson E, Oesch P, Simcoe RA, Wuyts S. 2026. The warm outer layer of a little red dot as the source of [Fe ii] and collisional Balmer lines with scattering wings. Astronomy &#38; Astrophysics. 707, A75.","apa":"Torralba Torregrosa, A., Matthee, J. J., Pezzulli, G., Naidu, R. P., Ishikawa, Y., Brammer, G. B., … Wuyts, S. (2026). The warm outer layer of a little red dot as the source of [Fe ii] and collisional Balmer lines with scattering wings. <i>Astronomy &#38; Astrophysics</i>. EDP Sciences. <a href=\"https://doi.org/10.1051/0004-6361/202557537\">https://doi.org/10.1051/0004-6361/202557537</a>","mla":"Torralba Torregrosa, Alberto, et al. “The Warm Outer Layer of a Little Red Dot as the Source of [Fe Ii] and Collisional Balmer Lines with Scattering Wings.” <i>Astronomy &#38; Astrophysics</i>, vol. 707, A75, EDP Sciences, 2026, doi:<a href=\"https://doi.org/10.1051/0004-6361/202557537\">10.1051/0004-6361/202557537</a>.","ieee":"A. Torralba Torregrosa <i>et al.</i>, “The warm outer layer of a little red dot as the source of [Fe ii] and collisional Balmer lines with scattering wings,” <i>Astronomy &#38; Astrophysics</i>, vol. 707. EDP Sciences, 2026.","short":"A. Torralba Torregrosa, J.J. Matthee, G. Pezzulli, R.P. Naidu, Y. Ishikawa, G.B. Brammer, S.J. Chang, J. Chisholm, A. De Graaff, F. D’Eugenio, C. Di Cesare, A.C. Eilers, J.E. Greene, M. Gronke, E. Iani, V. Kokorev, G. Kotiwale, I. Kramarenko, Y. Ma, S. Mascia, B. Navarrete, E. Nelson, P. Oesch, R.A. Simcoe, S. Wuyts, Astronomy &#38; Astrophysics 707 (2026).","chicago":"Torralba Torregrosa, Alberto, Jorryt J Matthee, Gabriele Pezzulli, Rohan P. Naidu, Yuzo Ishikawa, Gabriel B. Brammer, Seok Jun Chang, et al. “The Warm Outer Layer of a Little Red Dot as the Source of [Fe Ii] and Collisional Balmer Lines with Scattering Wings.” <i>Astronomy &#38; Astrophysics</i>. EDP Sciences, 2026. <a href=\"https://doi.org/10.1051/0004-6361/202557537\">https://doi.org/10.1051/0004-6361/202557537</a>.","ama":"Torralba Torregrosa A, Matthee JJ, Pezzulli G, et al. The warm outer layer of a little red dot as the source of [Fe ii] and collisional Balmer lines with scattering wings. <i>Astronomy &#38; Astrophysics</i>. 2026;707. doi:<a href=\"https://doi.org/10.1051/0004-6361/202557537\">10.1051/0004-6361/202557537</a>"}},{"date_created":"2026-05-10T22:02:15Z","project":[{"grant_number":"101076224","name":"Young galaxies as tracers and agents of cosmic reionization","_id":"bd9b2118-d553-11ed-ba76-db24564edfea"}],"quality_controlled":"1","doi":"10.3847/2041-8213/ae58a5","scopus_import":"1","oa_version":"Published Version","_id":"21846","article_type":"original","DOAJ_listed":"1","file_date_updated":"2026-05-11T06:44:37Z","OA_place":"publisher","language":[{"iso":"eng"}],"user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","publication_identifier":{"eissn":["2041-8213"],"issn":["2041-8205"]},"arxiv":1,"title":"Connecting the dots: UV-bright companions of Little Red Dots as Lyman–Werner sources enabling direct-collapse Black Hole formation","article_processing_charge":"Yes","type":"journal_article","oa":1,"external_id":{"arxiv":["2602.02702"]},"day":"10","publisher":"IOP Publishing","OA_type":"gold","publication_status":"published","year":"2026","department":[{"_id":"ZoHa"},{"_id":"JoMa"}],"PlanS_conform":"1","date_updated":"2026-05-11T06:48:33Z","intvolume":"      1002","has_accepted_license":"1","citation":{"ista":"Baggen JFW, Scoggins MT, Van Dokkum P, Haiman Z, Torralba Torregrosa A, Matthee JJ. 2026. Connecting the dots: UV-bright companions of Little Red Dots as Lyman–Werner sources enabling direct-collapse Black Hole formation. The Astrophysical Journal Letters. 1002(1), L4.","chicago":"Baggen, Josephine F.W., Matthew T. Scoggins, Pieter Van Dokkum, Zoltán Haiman, Alberto Torralba Torregrosa, and Jorryt J Matthee. “Connecting the Dots: UV-Bright Companions of Little Red Dots as Lyman–Werner Sources Enabling Direct-Collapse Black Hole Formation.” <i>The Astrophysical Journal Letters</i>. IOP Publishing, 2026. <a href=\"https://doi.org/10.3847/2041-8213/ae58a5\">https://doi.org/10.3847/2041-8213/ae58a5</a>.","ama":"Baggen JFW, Scoggins MT, Van Dokkum P, Haiman Z, Torralba Torregrosa A, Matthee JJ. Connecting the dots: UV-bright companions of Little Red Dots as Lyman–Werner sources enabling direct-collapse Black Hole formation. <i>The Astrophysical Journal Letters</i>. 2026;1002(1). doi:<a href=\"https://doi.org/10.3847/2041-8213/ae58a5\">10.3847/2041-8213/ae58a5</a>","apa":"Baggen, J. F. W., Scoggins, M. T., Van Dokkum, P., Haiman, Z., Torralba Torregrosa, A., &#38; Matthee, J. J. (2026). Connecting the dots: UV-bright companions of Little Red Dots as Lyman–Werner sources enabling direct-collapse Black Hole formation. <i>The Astrophysical Journal Letters</i>. IOP Publishing. <a href=\"https://doi.org/10.3847/2041-8213/ae58a5\">https://doi.org/10.3847/2041-8213/ae58a5</a>","mla":"Baggen, Josephine F. W., et al. “Connecting the Dots: UV-Bright Companions of Little Red Dots as Lyman–Werner Sources Enabling Direct-Collapse Black Hole Formation.” <i>The Astrophysical Journal Letters</i>, vol. 1002, no. 1, L4, IOP Publishing, 2026, doi:<a href=\"https://doi.org/10.3847/2041-8213/ae58a5\">10.3847/2041-8213/ae58a5</a>.","ieee":"J. F. W. Baggen, M. T. Scoggins, P. Van Dokkum, Z. Haiman, A. Torralba Torregrosa, and J. J. Matthee, “Connecting the dots: UV-bright companions of Little Red Dots as Lyman–Werner sources enabling direct-collapse Black Hole formation,” <i>The Astrophysical Journal Letters</i>, vol. 1002, no. 1. IOP Publishing, 2026.","short":"J.F.W. Baggen, M.T. Scoggins, P. Van Dokkum, Z. Haiman, A. Torralba Torregrosa, J.J. Matthee, The Astrophysical Journal Letters 1002 (2026)."},"abstract":[{"text":"We compile a sample of 83 little red dots (LRDs) with JWST imaging and find that a substantial fraction (∼43%, rising to ≳80% for the most luminous LRDs) host one or more spatially offset, UV-bright companions at projected separations of 0.5 kpc ≲ d ≲ 5 kpc, with median 〈d〉 = 1.0 kpc. This fraction is even higher when smaller spatial scales are probed at high signal-to-noise ratio: the two most strongly lensed LRDs, A383-LRD1 and the newly discovered A68-LRD1, both have UV-bright companions at separations of only d ∼ 0.3 kpc, below the resolution limit of most unlensed JWST samples. We explore whether these ubiquitous red/blue configurations may be physically linked to the formation of LRDs, in analogy with the “synchronized pair” scenario originally proposed for direct-collapse black hole formation. In this picture, UV radiation from the companions, with typically modest stellar masses (M∗ ∼ 108−109 M⊙), suppresses molecular hydrogen cooling in nearby gas, allowing nearly isothermal collapse and the formation of extremely compact objects, such as massive black holes, supermassive stars, or quasi-stars. Using component-resolved photometry and spectral energy distribution modeling, we infer Lyman–Werner radiation fields of J21,LW ∼ 102.5–105 at the locations of the red components, comparable to those required in direct-collapse models, suggesting that the necessary photodissociation conditions are realized in many LRD systems. This framework provides a simple and self-consistent explanation for the extreme compactness and distinctive spectral properties of LRDs and links long-standing theoretical models for early compact object formation directly to a population now observed with JWST in the early Universe.","lang":"eng"}],"tmp":{"short":"CC BY (4.0)","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","image":"/images/cc_by.png","legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode"},"date_published":"2026-04-10T00:00:00Z","file":[{"checksum":"8c31d8603cd6ad39c772a72d136dc3f8","relation":"main_file","access_level":"open_access","date_created":"2026-05-11T06:44:37Z","date_updated":"2026-05-11T06:44:37Z","creator":"dernst","content_type":"application/pdf","file_size":13359642,"file_id":"21851","file_name":"2026_AstrophysicalJourLetters_Baggen.pdf","success":1}],"ddc":["520"],"article_number":"L4","acknowledgement":"We thank Earl Bellinger, Fabio Pacucci, Andrea Ferrara, and Dale Kocevski for useful discussions. This work is based on observations made with the NASA/ESA/CSA James Webb Space Telescope. The data were obtained from the Mikulski Archive for Space Telescopes at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-03127 for JWST. These imaging observations are associated with programs 1345, 1180, 1181, 1243, 6882, 2561, 1324, 4111, and 1895. The compiled dataset can be accessed at doi:10.17909/1m8f-9c47. The Cosmic Dawn Center (DAWN) is funded by the Danish National Research Foundation under grant DNRF140. J.M. and A.T. acknowledge funding by the European Union (ERC, AGENTS, 101076224). This work was performed in part at Aspen Center for Physics, which is supported by National Science Foundation grant PHY-2210452. This work used the following Python packages: Matplotlib (J. D. Hunter 2007), SciPy (P. Virtanen et al. 2020), NumPy (S. van der Walt et al. 2011), AstroPy (Astropy Collaboration et al. 2022), colossus (B. Diemer 2018), and photutils (L. Bradley et al. 2025).","volume":1002,"month":"04","publication":"The Astrophysical Journal Letters","issue":"1","author":[{"last_name":"Baggen","first_name":"Josephine F.W.","full_name":"Baggen, Josephine F.W."},{"full_name":"Scoggins, Matthew T.","first_name":"Matthew T.","last_name":"Scoggins"},{"full_name":"Van Dokkum, Pieter","first_name":"Pieter","last_name":"Van Dokkum"},{"last_name":"Haiman","orcid":"0000-0003-3633-5403","first_name":"Zoltán","full_name":"Haiman, Zoltán","id":"7c006e8c-cc0d-11ee-8322-cb904ef76f36"},{"first_name":"Alberto","orcid":"0000-0001-5586-6950","last_name":"Torralba Torregrosa","id":"018f0249-0e87-11f0-b167-cbce08fbd541","full_name":"Torralba Torregrosa, Alberto"},{"full_name":"Matthee, Jorryt J","id":"7439a258-f3c0-11ec-9501-9df22fe06720","orcid":"0000-0003-2871-127X","last_name":"Matthee","first_name":"Jorryt J"}],"status":"public"},{"external_id":{"isi":["001507317300003"],"arxiv":["2501.04077"]},"day":"01","oa":1,"type":"journal_article","department":[{"_id":"JoMa"}],"OA_type":"diamond","year":"2025","publication_status":"published","publisher":"EDP Sciences","arxiv":1,"publication_identifier":{"eissn":["1432-0746"],"issn":["0004-6361"]},"user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","article_processing_charge":"No","title":"zELDA II: Reconstruction of galactic Lyman-alpha spectra attenuated by the intergalactic medium using neural networks","_id":"19929","scopus_import":"1","oa_version":"Published Version","doi":"10.1051/0004-6361/202453547","OA_place":"publisher","file_date_updated":"2025-06-30T08:28:40Z","language":[{"iso":"eng"}],"article_type":"original","isi":1,"date_created":"2025-06-29T22:01:15Z","quality_controlled":"1","publication":"Astronomy & Astrophysics","status":"public","author":[{"first_name":"Siddhartha","last_name":"Gurung-López","full_name":"Gurung-López, Siddhartha"},{"first_name":"Chris","last_name":"Byrohl","full_name":"Byrohl, Chris"},{"full_name":"Gronke, Max","last_name":"Gronke","first_name":"Max"},{"full_name":"Spinoso, Daniele","first_name":"Daniele","last_name":"Spinoso"},{"orcid":"0000-0001-5586-6950","last_name":"Torralba Torregrosa","first_name":"Alberto","id":"018f0249-0e87-11f0-b167-cbce08fbd541","full_name":"Torralba Torregrosa, Alberto"},{"full_name":"Fernández-Soto, Alberto","first_name":"Alberto","last_name":"Fernández-Soto"},{"full_name":"Arnalte-Mur, Pablo","last_name":"Arnalte-Mur","first_name":"Pablo"},{"full_name":"Martínez, Vicent J.","last_name":"Martínez","first_name":"Vicent J."}],"file":[{"file_id":"19933","success":1,"file_name":"2025_AstronomyAstrophysics_GurungLopez.pdf","content_type":"application/pdf","file_size":5758102,"date_created":"2025-06-30T08:28:40Z","access_level":"open_access","creator":"dernst","date_updated":"2025-06-30T08:28:40Z","checksum":"a50a817b72f03534c6a867035b51e433","relation":"main_file"}],"month":"06","volume":698,"acknowledgement":"The authors acknowledge the financial support from the MICIU with funding from the European Union NextGenerationEU and Generalitat Valenciana in the call Programa de Planes Complementarios de I+D+i (PRTR 2022) Project (VAL-JPAS), reference ASFAE/2022/025. This work is part of the research Project PID2023-149420NB-I00 funded by MICIU/AEI/10.13039/501100011033 and by ERDF/EU. This work is also supported by the project of excellence PROMETEO CIPROM/2023/21 of the Conselleria de Educación, Universidades y Empleo (Generalitat Valenciana). MG thanks the Max Planck Society for support through the Max Planck Research Group. DS acknowledges the support by the Tsinghua Shui Mu Scholarship, funding of the National Key R&D Program of China (grant no. 2023YFA1605600), the science research grants from the China Manned Space Project with no. CMS-CSST2021-A05, and the Tsinghua University Initiative Scientific Research Program (no. 20223080023). This research made use of matplotlib, a Python library for publication quality graphics (Hunter 2007), NumPy (Harris et al. 2020) and SciPy (Virtanen et al. 2020).","article_number":"A139","ddc":["520"],"citation":{"chicago":"Gurung-López, Siddhartha, Chris Byrohl, Max Gronke, Daniele Spinoso, Alberto Torralba Torregrosa, Alberto Fernández-Soto, Pablo Arnalte-Mur, and Vicent J. Martínez. “ZELDA II: Reconstruction of Galactic Lyman-Alpha Spectra Attenuated by the Intergalactic Medium Using Neural Networks.” <i>Astronomy &#38; Astrophysics</i>. EDP Sciences, 2025. <a href=\"https://doi.org/10.1051/0004-6361/202453547\">https://doi.org/10.1051/0004-6361/202453547</a>.","ama":"Gurung-López S, Byrohl C, Gronke M, et al. zELDA II: Reconstruction of galactic Lyman-alpha spectra attenuated by the intergalactic medium using neural networks. <i>Astronomy &#38; Astrophysics</i>. 2025;698. doi:<a href=\"https://doi.org/10.1051/0004-6361/202453547\">10.1051/0004-6361/202453547</a>","apa":"Gurung-López, S., Byrohl, C., Gronke, M., Spinoso, D., Torralba Torregrosa, A., Fernández-Soto, A., … Martínez, V. J. (2025). zELDA II: Reconstruction of galactic Lyman-alpha spectra attenuated by the intergalactic medium using neural networks. <i>Astronomy &#38; Astrophysics</i>. EDP Sciences. <a href=\"https://doi.org/10.1051/0004-6361/202453547\">https://doi.org/10.1051/0004-6361/202453547</a>","ieee":"S. Gurung-López <i>et al.</i>, “zELDA II: Reconstruction of galactic Lyman-alpha spectra attenuated by the intergalactic medium using neural networks,” <i>Astronomy &#38; Astrophysics</i>, vol. 698. EDP Sciences, 2025.","short":"S. Gurung-López, C. Byrohl, M. Gronke, D. Spinoso, A. Torralba Torregrosa, A. Fernández-Soto, P. Arnalte-Mur, V.J. Martínez, Astronomy &#38; Astrophysics 698 (2025).","mla":"Gurung-López, Siddhartha, et al. “ZELDA II: Reconstruction of Galactic Lyman-Alpha Spectra Attenuated by the Intergalactic Medium Using Neural Networks.” <i>Astronomy &#38; Astrophysics</i>, vol. 698, A139, EDP Sciences, 2025, doi:<a href=\"https://doi.org/10.1051/0004-6361/202453547\">10.1051/0004-6361/202453547</a>.","ista":"Gurung-López S, Byrohl C, Gronke M, Spinoso D, Torralba Torregrosa A, Fernández-Soto A, Arnalte-Mur P, Martínez VJ. 2025. zELDA II: Reconstruction of galactic Lyman-alpha spectra attenuated by the intergalactic medium using neural networks. Astronomy &#38; Astrophysics. 698, A139."},"abstract":[{"text":"Context. The observed Lyman-alpha (Lyα) line profile is a convolution of the complex Lyα radiative transfer taking place in the interstellar, circumgalactic, and intergalactic media (ISM, CGM, and IGM, respectively). Discerning the different components of the Lyα line is crucial in order to use it as a probe of galaxy formation or the evolution of the IGM.\r\n\r\nAims. We aim to present the second version of zELDA (redshift Estimator for Line profiles of Distant Lyman-Alpha emitters), an open-source Python module focused on modelling and fitting observed Lyα line profiles. This new version of zELDA focuses on disentangling the galactic from the IGM effects.\r\n\r\nMethods. We built realistic Lyα line profiles that include the ISM and IGM contributions by combining the Monte Carlo radiative-transfer simulations for the so-called shell model (ISM) and IGM transmission curves generated from TNG100. We used these mock line profiles to train different artificial neural networks. These use the observed spectrum as input and the outflow parameters of the best fitting ‘shell model’ as output along with the redshift and Lyα emission IGM escape fraction of the source.\r\n\r\nResults. We measured the accuracy of zELDA on mock Lyα line profiles. We find that zELDA is capable of reconstructing the ISM emerging Lyα line profile with high levels of accuracy (Kolmogórov-Smirnov<0.1) for 95% of the cases for HST/COS-like observations and 80% for MUSE-WIDE-like observations. zELDA is able to measure the IGM transmission with typical uncertainties below 10% for HST/COS and MUSE-WIDE data.\r\n\r\nConclusions. This work represents a step forward in the high-precision reconstruction of IGM-attenuated Lyα line profiles. zELDA allows the disentanglement of the galactic and IGM contribution shaping the Lyα line shape and thus allows us to use Lyα as a tool to study galaxy and ISM evolution.","lang":"eng"}],"has_accepted_license":"1","date_published":"2025-06-01T00:00:00Z","tmp":{"short":"CC BY (4.0)","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","image":"/images/cc_by.png","legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode"},"date_updated":"2026-02-16T12:11:56Z","intvolume":"       698"},{"abstract":[{"text":"JWST observations have unveiled faint active galactic nuclei (AGNs) at high redshift that provide insights into the formation of supermassive black holes (SMBHs). However, disentangling their stellar from AGN light is challenging. Here, we use an empirical approach to infer the average stellar mass of five faint broad-line (BL) Hα emitters at z = 4–5 with BH masses ≈6 × 10^6 M⊙, with a method independent of their spectral energy distribution (SED). We use the deep JWST/NIRcam grism survey “All the Little Things” to measure the overdensities around BL-Hα emitters and around a spectroscopic reference sample of ∼300 galaxies. In our reference sample, we find that megaparsec-scale overdensity correlates with stellar mass. Their large-scale environments suggest that BL-Hα emitters are hosted by galaxies with stellar masses ≈5 × 10^7 M⊙, ≈40 times lower than those inferred from galaxy-only SED fits. Adding measurements around more luminous z ≈ 6 AGNs, we find tentative correlations between line width, BH mass, and the overdensity, suggestive of a steep BH to halo mass relation. The main implications are (1) when BH masses are taken at face value, we confirm extremely high BH to stellar mass ratios of ≈10%, (2) the galaxies of low stellar mass that host growing SMBHs are in tension with typical hydrodynamical simulations, except those without feedback, (3) a 1% duty cycle implied by the host mass hints at super-Eddington accretion, (4) the masses are at odds with an interpretation of the line broadening in terms of high stellar density, (5) our results imply a luminosity-dependent diversity of galaxy masses, environments, and SEDs among AGN samples.","lang":"eng"}],"citation":{"ista":"Matthee JJ, Naidu RP, Kotiwale G, Furtak LJ, Kramarenko I, Mackenzie R, Greene J, Adamo A, Bouwens RJ, Di Cesare C, Eilers A-C, de Graaff A, Heintz KE, Kashino D, Maseda MV, Tacchella S, Torralba Torregrosa A. 2025. Environmental evidence for overly massive Black Holes in low-mass galaxies and a Black Hole–Halo mass relation at z ∼ 5. The Astrophysical Journal. 988(2), 246.","chicago":"Matthee, Jorryt J, Rohan P. Naidu, Gauri Kotiwale, Lukas J. Furtak, Ivan Kramarenko, Ruari Mackenzie, Jenny Greene, et al. “Environmental Evidence for Overly Massive Black Holes in Low-Mass Galaxies and a Black Hole–Halo Mass Relation at z ∼ 5.” <i>The Astrophysical Journal</i>. IOP Publishing, 2025. <a href=\"https://doi.org/10.3847/1538-4357/ade886\">https://doi.org/10.3847/1538-4357/ade886</a>.","ama":"Matthee JJ, Naidu RP, Kotiwale G, et al. Environmental evidence for overly massive Black Holes in low-mass galaxies and a Black Hole–Halo mass relation at z ∼ 5. <i>The Astrophysical Journal</i>. 2025;988(2). doi:<a href=\"https://doi.org/10.3847/1538-4357/ade886\">10.3847/1538-4357/ade886</a>","apa":"Matthee, J. J., Naidu, R. P., Kotiwale, G., Furtak, L. J., Kramarenko, I., Mackenzie, R., … Torralba Torregrosa, A. (2025). Environmental evidence for overly massive Black Holes in low-mass galaxies and a Black Hole–Halo mass relation at z ∼ 5. <i>The Astrophysical Journal</i>. IOP Publishing. <a href=\"https://doi.org/10.3847/1538-4357/ade886\">https://doi.org/10.3847/1538-4357/ade886</a>","ieee":"J. J. Matthee <i>et al.</i>, “Environmental evidence for overly massive Black Holes in low-mass galaxies and a Black Hole–Halo mass relation at z ∼ 5,” <i>The Astrophysical Journal</i>, vol. 988, no. 2. IOP Publishing, 2025.","short":"J.J. Matthee, R.P. Naidu, G. Kotiwale, L.J. Furtak, I. Kramarenko, R. Mackenzie, J. Greene, A. Adamo, R.J. Bouwens, C. Di Cesare, A.-C. Eilers, A. de Graaff, K.E. Heintz, D. Kashino, M.V. Maseda, S. Tacchella, A. Torralba Torregrosa, The Astrophysical Journal 988 (2025).","mla":"Matthee, Jorryt J., et al. “Environmental Evidence for Overly Massive Black Holes in Low-Mass Galaxies and a Black Hole–Halo Mass Relation at z ∼ 5.” <i>The Astrophysical Journal</i>, vol. 988, no. 2, 246, IOP Publishing, 2025, doi:<a href=\"https://doi.org/10.3847/1538-4357/ade886\">10.3847/1538-4357/ade886</a>."},"has_accepted_license":"1","corr_author":"1","date_published":"2025-07-29T00:00:00Z","tmp":{"short":"CC BY (4.0)","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","image":"/images/cc_by.png","legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode"},"date_updated":"2026-02-09T08:22:01Z","intvolume":"       988","publication":"The Astrophysical Journal","issue":"2","status":"public","author":[{"first_name":"Jorryt J","last_name":"Matthee","orcid":"0000-0003-2871-127X","id":"7439a258-f3c0-11ec-9501-9df22fe06720","full_name":"Matthee, Jorryt J"},{"full_name":"Naidu, Rohan P.","first_name":"Rohan P.","last_name":"Naidu"},{"id":"1438afc8-1ff6-11ee-9fa6-cd4a75d66875","full_name":"Kotiwale, Gauri","last_name":"Kotiwale","first_name":"Gauri"},{"last_name":"Furtak","first_name":"Lukas J.","full_name":"Furtak, Lukas J."},{"full_name":"Kramarenko, Ivan","id":"9a9394cb-3200-11ee-973b-f5ba2a8b16e4","orcid":"0000-0001-5346-6048","last_name":"Kramarenko","first_name":"Ivan"},{"last_name":"Mackenzie","first_name":"Ruari","full_name":"Mackenzie, Ruari"},{"full_name":"Greene, Jenny","last_name":"Greene","first_name":"Jenny"},{"first_name":"Angela","last_name":"Adamo","full_name":"Adamo, Angela"},{"last_name":"Bouwens","first_name":"Rychard J.","full_name":"Bouwens, Rychard J."},{"id":"2d002343-372f-11ef-98ec-a164d20427cb","full_name":"Di Cesare, Claudia","first_name":"Claudia","last_name":"Di Cesare"},{"full_name":"Eilers, Anna-Christina","first_name":"Anna-Christina","last_name":"Eilers"},{"full_name":"de Graaff, Anna","last_name":"de Graaff","first_name":"Anna"},{"full_name":"Heintz, Kasper E.","last_name":"Heintz","first_name":"Kasper E."},{"full_name":"Kashino, Daichi","first_name":"Daichi","last_name":"Kashino"},{"full_name":"Maseda, Michael V.","first_name":"Michael V.","last_name":"Maseda"},{"first_name":"Sandro","last_name":"Tacchella","full_name":"Tacchella, Sandro"},{"first_name":"Alberto","last_name":"Torralba Torregrosa","orcid":"0000-0001-5586-6950","full_name":"Torralba Torregrosa, Alberto","id":"018f0249-0e87-11f0-b167-cbce08fbd541"}],"file":[{"date_created":"2026-02-09T08:20:14Z","access_level":"open_access","creator":"dernst","date_updated":"2026-02-09T08:20:14Z","checksum":"a49fbed72f2ff9c0b13129acb6f44f9d","relation":"main_file","file_id":"21168","success":1,"file_name":"2025_AstrophysicalJournal_Matthee.pdf","content_type":"application/pdf","file_size":6237415}],"month":"07","volume":988,"acknowledgement":"We thank the referee for their constructive comments that helped to improve the paper. We thank Junyao Li for sharing model output shown in Figure 13, Rob Crain for sharing results from the ONLYAGN EAGLE model shown in Figure 15, and Adi Zitrin for comments. This work is based on observations made with the NASA/ESA/CSA James Webb Space Telescope. The data were obtained from the Mikulski Archive for Space Telescopes at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-03127 for JWST. These observations are associated with programs # 3516. Funded by the European Union (ERC, AGENTS, 101076224). Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Research Council. Neither the European Union nor the granting authority can be held responsible for them. We acknowledge funding from JWST program GO-3516. Support for this work was provided by NASA through the NASA Hubble Fellowship grant HST-HF2-51515.001-A awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Incorporated, under NASA contract NAS 5-26555. A.A. acknowledges support by the Swedish research council Vetenskapsrådet (2021-05559).","ddc":["520"],"article_number":"246","_id":"21062","oa_version":"Published Version","scopus_import":"1","doi":"10.3847/1538-4357/ade886","OA_place":"publisher","language":[{"iso":"eng"}],"file_date_updated":"2026-02-09T08:20:14Z","DOAJ_listed":"1","article_type":"original","date_created":"2026-01-28T15:25:42Z","quality_controlled":"1","project":[{"grant_number":"101076224","name":"Young galaxies as tracers and agents of cosmic reionization","_id":"bd9b2118-d553-11ed-ba76-db24564edfea"}],"day":"29","external_id":{"arxiv":["2412.02846"]},"oa":1,"type":"journal_article","PlanS_conform":"1","department":[{"_id":"JoMa"}],"year":"2025","publication_status":"published","OA_type":"gold","publisher":"IOP Publishing","arxiv":1,"publication_identifier":{"issn":["0004-637X"],"eissn":["1538-4357"]},"user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","article_processing_charge":"Yes","title":"Environmental evidence for overly massive Black Holes in low-mass galaxies and a Black Hole–Halo mass relation at z ∼ 5"}]