{"external_id":{"arxiv":["2405.01473"]},"_id":"17234","volume":969,"author":[{"full_name":"Wang, Bingjie","last_name":"Wang","first_name":"Bingjie"},{"first_name":"Joel","full_name":"Leja, Joel","last_name":"Leja"},{"full_name":"De Graaff, Anna","last_name":"De Graaff","first_name":"Anna"},{"last_name":"Brammer","full_name":"Brammer, Gabriel B.","first_name":"Gabriel B."},{"full_name":"Weibel, Andrea","last_name":"Weibel","first_name":"Andrea"},{"last_name":"Van Dokkum","full_name":"Van Dokkum, Pieter","first_name":"Pieter"},{"last_name":"Baggen","full_name":"Baggen, Josephine F.W.","first_name":"Josephine F.W."},{"last_name":"Suess","full_name":"Suess, Katherine A.","first_name":"Katherine A."},{"full_name":"Greene, Jenny E.","last_name":"Greene","first_name":"Jenny E."},{"first_name":"Rachel","last_name":"Bezanson","full_name":"Bezanson, Rachel"},{"last_name":"Cleri","full_name":"Cleri, Nikko J.","first_name":"Nikko J."},{"last_name":"Hirschmann","full_name":"Hirschmann, Michaela","first_name":"Michaela"},{"last_name":"Labbé","full_name":"Labbé, Ivo","first_name":"Ivo"},{"last_name":"Matthee","full_name":"Matthee, Jorryt J","id":"7439a258-f3c0-11ec-9501-9df22fe06720","orcid":"0000-0003-2871-127X","first_name":"Jorryt J"},{"full_name":"Mcconachie, Ian","last_name":"Mcconachie","first_name":"Ian"},{"first_name":"Rohan P.","full_name":"Naidu, Rohan P.","last_name":"Naidu"},{"first_name":"Erica","last_name":"Nelson","full_name":"Nelson, Erica"},{"first_name":"Pascal A.","full_name":"Oesch, Pascal A.","last_name":"Oesch"},{"full_name":"Setton, David J.","last_name":"Setton","first_name":"David J."},{"first_name":"Christina C.","last_name":"Williams","full_name":"Williams, Christina C."}],"doi":"10.3847/2041-8213/ad55f7","day":"01","publication_status":"published","publication":"Astrophysical Journal Letters","date_published":"2024-07-01T00:00:00Z","file":[{"file_size":3273303,"date_updated":"2024-07-16T06:24:29Z","content_type":"application/pdf","creator":"dernst","file_id":"17243","checksum":"bb1a6725586df12e745d091b5778bb2b","success":1,"date_created":"2024-07-16T06:24:29Z","file_name":"2024_AstrophysicalJourn_Wang.pdf","access_level":"open_access","relation":"main_file"}],"user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","file_date_updated":"2024-07-16T06:24:29Z","tmp":{"legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode","short":"CC BY (4.0)","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","image":"/images/cc_by.png"},"oa":1,"language":[{"iso":"eng"}],"quality_controlled":"1","license":"https://creativecommons.org/licenses/by/4.0/","intvolume":"       969","scopus_import":"1","article_processing_charge":"Yes","acknowledgement":"We thank the anonymous referee for the helpful comments. B.W. and J.L. acknowledge support from JWST-GO04233.009-A. The Cosmic Dawn Center is funded by the Danish National Research Foundation (DNRF) under grant No. 140. This research was supported by the International Space Science Institute (ISSI) in Bern, through ISSI International Team project No. 562 (First Light at Cosmic Dawn: Exploiting the James Webb Space Telescope Revolution). 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. The JWST data presented in this Letter were obtained from the Mikulski Archive for Space Telescopes (MAST) at the Space Telescope Science Institute. The specific observations analyzed can be accessed via doi:10.17909/3a4n-9p88. Computations for this research were performed on the Pennsylvania State University’s Institute for Computational and Data Sciences’ Roar supercomputer. This publication made use of the NASA Astrophysical Data System for bibliographic information. \r\nFacilities: HST (ACS, WFC3), JWST (NIRCam, NIRSpec). Software: Astropy (Astropy Collaboration et al. 2013, 2018, 2022), dynesty (Speagle 2020), EAzY (Brammer et al. 2008),\r\nemcee (Foreman-Mackey et al. 2013), Matplotlib (Hunter 2007), msaexp (Brammer 2023b), msafit (de Graaff et al. 2024a), NumPy (Harris et al. 2020), Prospector (Johnson et al. 2021), Python-FSPS (Johnson et al. 2023).","date_updated":"2024-07-16T06:26:50Z","month":"07","title":"RUBIES: Evolved stellar populations with extended formation histories at z ∼ 7-8 in candidate massive galaxies identified with JWST/NIRSpec","type":"journal_article","citation":{"apa":"Wang, B., Leja, J., De Graaff, A., Brammer, G. B., Weibel, A., Van Dokkum, P., … Williams, C. C. (2024). RUBIES: Evolved stellar populations with extended formation histories at z ∼ 7-8 in candidate massive galaxies identified with JWST/NIRSpec. <i>Astrophysical Journal Letters</i>. IOP Publishing. <a href=\"https://doi.org/10.3847/2041-8213/ad55f7\">https://doi.org/10.3847/2041-8213/ad55f7</a>","chicago":"Wang, Bingjie, Joel Leja, Anna De Graaff, Gabriel B. Brammer, Andrea Weibel, Pieter Van Dokkum, Josephine F.W. Baggen, et al. “RUBIES: Evolved Stellar Populations with Extended Formation Histories at z ∼ 7-8 in Candidate Massive Galaxies Identified with JWST/NIRSpec.” <i>Astrophysical Journal Letters</i>. IOP Publishing, 2024. <a href=\"https://doi.org/10.3847/2041-8213/ad55f7\">https://doi.org/10.3847/2041-8213/ad55f7</a>.","mla":"Wang, Bingjie, et al. “RUBIES: Evolved Stellar Populations with Extended Formation Histories at z ∼ 7-8 in Candidate Massive Galaxies Identified with JWST/NIRSpec.” <i>Astrophysical Journal Letters</i>, vol. 969, no. 1, L13, IOP Publishing, 2024, doi:<a href=\"https://doi.org/10.3847/2041-8213/ad55f7\">10.3847/2041-8213/ad55f7</a>.","ieee":"B. Wang <i>et al.</i>, “RUBIES: Evolved stellar populations with extended formation histories at z ∼ 7-8 in candidate massive galaxies identified with JWST/NIRSpec,” <i>Astrophysical Journal Letters</i>, vol. 969, no. 1. IOP Publishing, 2024.","ama":"Wang B, Leja J, De Graaff A, et al. RUBIES: Evolved stellar populations with extended formation histories at z ∼ 7-8 in candidate massive galaxies identified with JWST/NIRSpec. <i>Astrophysical Journal Letters</i>. 2024;969(1). doi:<a href=\"https://doi.org/10.3847/2041-8213/ad55f7\">10.3847/2041-8213/ad55f7</a>","short":"B. Wang, J. Leja, A. De Graaff, G.B. Brammer, A. Weibel, P. Van Dokkum, J.F.W. Baggen, K.A. Suess, J.E. Greene, R. Bezanson, N.J. Cleri, M. Hirschmann, I. Labbé, J.J. Matthee, I. Mcconachie, R.P. Naidu, E. Nelson, P.A. Oesch, D.J. Setton, C.C. Williams, Astrophysical Journal Letters 969 (2024).","ista":"Wang B, Leja J, De Graaff A, Brammer GB, Weibel A, Van Dokkum P, Baggen JFW, Suess KA, Greene JE, Bezanson R, Cleri NJ, Hirschmann M, Labbé I, Matthee JJ, Mcconachie I, Naidu RP, Nelson E, Oesch PA, Setton DJ, Williams CC. 2024. RUBIES: Evolved stellar populations with extended formation histories at z ∼ 7-8 in candidate massive galaxies identified with JWST/NIRSpec. Astrophysical Journal Letters. 969(1), L13."},"date_created":"2024-07-14T22:01:11Z","has_accepted_license":"1","article_number":"L13","article_type":"original","status":"public","department":[{"_id":"JoMa"}],"oa_version":"Published Version","publication_identifier":{"issn":["2041-8205"],"eissn":["2041-8213"]},"abstract":[{"lang":"eng","text":"The identification of red, apparently massive galaxies at z > 7 in early James Webb Space Telescope (JWST) photometry suggests a strongly accelerated time line compared to standard models of galaxy growth. A major uncertainty in the interpretation is whether the red colors are caused by evolved stellar populations, dust, or other effects such as emission lines or active galactic nuclei (AGNs). Here we show that three of the massive galaxy candidates at z = 6.7–8.4 have prominent Balmer breaks in JWST/NIRSpec spectroscopy from the RUBIES program. The Balmer breaks demonstrate unambiguously that stellar emission dominates at λrest = 0.4 μm and require formation histories extending hundreds of millions of years into the past in galaxies only 600–800 Myr after the big bang. Two of the three galaxies also show broad Balmer lines, with Hβ FWHM > 2500 km s−1, suggesting that dust-reddened AGNs contribute to, or even dominate, the spectral energy distributions of these galaxies at λrest ≳ 0.6 μm. All three galaxies have relatively narrow [O iii] lines, seemingly ruling out a high-mass interpretation if the lines arise in dynamically relaxed, inclined disks. Yet the inferred masses also remain highly uncertain. We model the high-quality spectra using Prospector to decompose the continuum into stellar and AGN components and explore limiting cases in stellar/AGN contribution. This produces a wide range of possible stellar masses, spanning M⋆ ∼ 109−1011M⊙. Nevertheless, all fits suggest a very early and rapid formation, most of which follow with a truncation in star formation. Potential origins and evolutionary tracks for these objects are discussed, from the cores of massive galaxies to low-mass galaxies with overmassive black holes. Intriguingly, we find all of these explanations to be incomplete; deeper and redder data are needed to understand the physics of these systems."}],"year":"2024","ddc":["520"],"issue":"1","publisher":"IOP Publishing"}