{"paper":{"title":"Discovery of a Broad-Line Active Galactic Nucleus at $z = 9.98$","arxiv_id":"2610.28735","primary_cat":"astro-ph.GA","submitted_at":"2026-10-20T18:00:03+00:00","version_compiled":"v1"},"notice":"Every quoted sentence is the authors' text from the arXiv listing abstract. Labels and probabilities are the outputs of classifier-1.13.0 on the question bank abstract-p1-20260923, exactly as returned. No sentence in this record was written by a language model.","schema":"pith.compiled-record/v0","status":"compiled","abstract":{"source":"arXiv listing abstract v1","sentences":[{"i":0,"p":0.96,"id":"s0","own":false,"role":"background","text":"The James Webb Space Telescope (JWST) has uncovered a previously unexplored population of faint active galactic nuclei (AGNs) in the early Universe.","hedge":{"p":1.0,"label":"asserted"},"own_p":0.21,"main_claim_p":0.06,"quantitative":false,"quantitative_p":0.05,"role_probabilities":{"gap":0.03,"method":0.0,"result":0.01,"background":0.96,"limitation":0.0,"future_work":0.0,"contribution":0.0,"interpretation":0.0}},{"i":1,"p":0.92,"id":"s1","own":true,"role":"contribution","text":"We present MoM-BL-z10 at $z=9.9837\\pm0.0009$, identified through a systematic search for broad-line AGNs at $z\\geq6$ using public JWST/NIRSpec PRISM spectra from the DAWN JWST Archive.","hedge":{"p":1.0,"label":"asserted"},"own_p":0.96,"main_claim_p":0.29,"quantitative":true,"quantitative_p":0.98,"role_probabilities":{"gap":0.0,"method":0.01,"result":0.07,"background":0.0,"limitation":0.0,"future_work":0.0,"contribution":0.92,"interpretation":0.0}},{"i":2,"p":0.98,"id":"s2","own":true,"role":"result","text":"The PRISM spectrum exhibits a broad component in H$\\beta$ at 5.35 microns.","hedge":{"p":1.0,"label":"asserted"},"own_p":0.85,"main_claim_p":0.03,"quantitative":true,"quantitative_p":0.94,"role_probabilities":{"gap":0.0,"method":0.02,"result":0.98,"background":0.0,"limitation":0.0,"future_work":0.0,"contribution":0.0,"interpretation":0.0}},{"i":3,"p":1.0,"id":"s3","own":true,"role":"result","text":"A narrow+broad Gaussian fit yields a broad H$\\beta$ detection at S/N = 3.87, with FWHM = $3480^{+2040}_{-950}$ km s$^{-1}$ and $L_{{\\rm H}\\beta,{\\rm broad}}=1.25^{+0.33}_{-0.31}\\times10^{42}$ erg s$^{-1}$.","hedge":{"p":1.0,"label":"asserted"},"own_p":0.96,"main_claim_p":0.06,"quantitative":true,"quantitative_p":0.99,"role_probabilities":{"gap":0.0,"method":0.0,"result":1.0,"background":0.0,"limitation":0.0,"future_work":0.0,"contribution":0.0,"interpretation":0.0}},{"i":4,"p":0.51,"id":"s4","own":true,"role":"interpretation","text":"The detection of [Ne III] $\\lambda3870$ and the high [Ne III]/[O II] and [O III]/H$\\beta$ ratios further support the AGN interpretation.","hedge":{"p":0.77,"label":"asserted"},"own_p":0.87,"main_claim_p":0.04,"quantitative":false,"quantitative_p":0.39,"role_probabilities":{"gap":0.0,"method":0.0,"result":0.49,"background":0.0,"limitation":0.0,"future_work":0.0,"contribution":0.0,"interpretation":0.51}},{"i":5,"p":0.69,"id":"s5","own":true,"role":"interpretation","text":"Its rest-frame UV and optical continuum slopes, compact NIRCam morphology, and a tentative MIRI F770W detection suggest similarities to Little Red Dots (LRDs).","hedge":{"p":0.99,"label":"hedged_possibility"},"own_p":0.87,"main_claim_p":0.04,"quantitative":false,"quantitative_p":0.27,"role_probabilities":{"gap":0.0,"method":0.0,"result":0.31,"background":0.0,"limitation":0.0,"future_work":0.0,"contribution":0.0,"interpretation":0.69}},{"i":6,"p":0.49,"id":"s6","own":true,"role":"contribution","text":"The broad H$\\beta$ detection enables the first virial SMBH mass estimate at $z\\sim10$.","hedge":{"p":0.98,"label":"asserted"},"own_p":0.77,"main_claim_p":0.18,"quantitative":false,"quantitative_p":0.37,"role_probabilities":{"gap":0.03,"method":0.01,"result":0.29,"background":0.0,"limitation":0.0,"future_work":0.0,"contribution":0.49,"interpretation":0.18}},{"i":7,"p":1.0,"id":"s7","own":true,"role":"result","text":"We derive $M_{\\rm BH}=3.6^{+5.8}_{-1.7}\\times10^7 M_\\odot$ and $\\lambda_{\\rm Edd}=0.11^{+0.10}_{-0.07}$ using the standard single-epoch virial calibration and quasar bolometric correction.","hedge":{"p":1.0,"label":"asserted"},"own_p":0.97,"main_claim_p":0.13,"quantitative":true,"quantitative_p":0.99,"role_probabilities":{"gap":0.0,"method":0.0,"result":1.0,"background":0.0,"limitation":0.0,"future_work":0.0,"contribution":0.0,"interpretation":0.0}},{"i":8,"p":0.9,"id":"s8","own":true,"role":"result","text":"We also consider an alternative scenario adopting the LRD-specific bolometric correction and assuming $\\lambda_{\\rm Edd}=1$, which yields $M_{\\rm BH}=2.1^{+0.6}_{-0.5}\\times10^6 M_\\odot$.","hedge":{"p":0.57,"label":"hedged_possibility"},"own_p":0.93,"main_claim_p":0.05,"quantitative":true,"quantitative_p":0.99,"role_probabilities":{"gap":0.0,"method":0.05,"result":0.9,"background":0.0,"limitation":0.01,"future_work":0.0,"contribution":0.02,"interpretation":0.02}},{"i":9,"p":1.0,"id":"s9","own":true,"role":"interpretation","text":"Under either scenario, the inferred SMBH mass at a cosmic age of only 470 Myr highlights the challenge of rapid BH growth in the early Universe, suggesting super-Eddington accretion from a stellar-mass seed or a more massive seed.","hedge":{"p":0.88,"label":"hedged_possibility"},"own_p":0.81,"main_claim_p":0.54,"quantitative":true,"quantitative_p":0.98,"role_probabilities":{"gap":0.0,"method":0.0,"result":0.0,"background":0.0,"limitation":0.0,"future_work":0.0,"contribution":0.0,"interpretation":1.0}},{"i":10,"p":0.61,"id":"s10","own":true,"role":"interpretation","text":"As the highest-redshift broad-line AGN identified to date, MoM-BL-z10 provides a new observational benchmark for understanding the early growth of supermassive black holes.","hedge":{"p":1.0,"label":"asserted"},"own_p":0.88,"main_claim_p":0.62,"quantitative":false,"quantitative_p":0.45,"role_probabilities":{"gap":0.0,"method":0.0,"result":0.03,"background":0.0,"limitation":0.0,"future_work":0.01,"contribution":0.35,"interpretation":0.61}}]},"compiled":{"main_claim":{"p":0.67,"text":"As the highest-redshift broad-line AGN identified to 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