A mature quasar at cosmic dawn revealed by JWST rest-frame infrared spectroscopy

Author(s): Sarah E.I. Bosman, Javier Álvarez-Márquez, Luis Colina, Fabian Walter, Almudena Alonso-Herrero, Martin J. Ward, Göran Östlin, Thomas R. Greve, Gillian Wright, Arjan Bik, Leindert Boogaard, Karina Caputi, Luca Costantin, Andreas Eckart, Macarena García-Marín, Steven Gillman, Jens Hjorth, Edoardo Iani, Olivier Ilbert, Iris Jermann, Alvaro Labiano, Danial Langeroodi, Florian Peißker, Pierluigi Rinaldi, Martin Topinka, Paul van der Werf, Manuel Güdel, Thomas Henning, Pierre Olivier Lagage, Tom P. Ray, Ewine F. van Dishoeck, Bart Vandenbussche
Abstract: The rapid assembly of the first supermassive black holes is an enduring mystery. Until now, it was not known whether quasar ‘feeding’ structures (the ‘hot torus’) could assemble as fast as the smaller-scale quasar structures. We present JWST/MRS (rest-frame infrared) spectroscopic observations of the quasar J1120+0641 at z = 7.0848 (well within the epoch of reionization). The hot torus dust was clearly detected at λ_rest ≃ 1.3 μm, with a black-body temperature of T_dust=1,413.5_−7.4^+5.7 K, slightly elevated compared to similarly luminous quasars at lower redshifts. Importantly, the supermassive black hole mass of J1120+0641 based on the Hα line (accessible only with JWST), M_BH = 1.52 ± 0.17 × 10⁹ M_⊙, is in good agreement with previous ground-based rest-frame ultraviolet Mg ii measurements. Comparing the ratios of the Hα, Paα and Paβ emission lines to predictions from a simple one-phase Cloudy model, we find that they are consistent with originating from a common broad-line region with physical parameters that are consistent with lower-redshift quasars. Together, this implies that J1120+0641’s accretion structures must have assembled very quickly, as they appear fully ‘mature’ less than 760 Myr after the Big Bang.
Organisation(s): Department of Astrophysics
External organisation(s): Scientific Software Center, Max-Planck-Institut für Astronomie, European Space Astronomy Centre (ESA), Durham University, Oskar Klein Centre, University of Copenhagen, Technical University of Denmark (DTU), University College London, The Royal Observatory, Edinburgh, University of Groningen, Universität zu Köln, Aix-Marseille Université, Dublin Institute for Advanced Studies, Leiden University, Eidgenössische Technische Hochschule Zürich, Université Paris Saclay, Katholieke Universiteit Leuven
Journal: Nature Astronomy
Volume: 8
Pages: 1054-1065
No. of pages: 12
ISSN: 2397-3366
DOI: https://doi.org/10.1038/s41550-024-02273-0
Publication date: 08-2024
Peer reviewed: Yes
Austrian Fields of Science 2012: 103003 Astronomy, 103004 Astrophysics
ASJC Scopus subject areas: Astronomy and Astrophysics
Portal url: https://ucrisportal.univie.ac.at/en/publications/6a4bc751-3937-4eb6-8158-16a07e4bbc3a

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