Spatially resolved broad-line region in a quasar at <i>z</i> = 4

We present the first near-infrared interferometric data of a QSO at z = 4. The K -band observations were performed with GRAVITY+ on the VLTI using all four UTs, detecting a differential phase signal that traces the spatially resolved kinematics for both the H β and H γ lines in the broad-line region (BLR). We fit the two lines simultaneously with an updated model that includes distinct rotating and conical outflowing components. For the best-fit model, more than 80% of the H I line emission from the BLR originates in an outflow with a velocity up to 10 4 km s −1 . This is oriented so that our line of sight is along an edge of the conical structure, which produces the prominent blue wing on the line profile. A combination of anisotropic line emission and mid-plane opacity leads to the single-sided phase signal. The model is able to qualitatively match both the outflowing C IV line profile and the systemic O I fluorescent emission. The black hole mass of 8 × 10 8 M ⊙ that we derive is the highest redshift black hole mass measurement to date obtained directly from BLR dynamics. It is an order of magnitude lower than that inferred from various single epoch scaling relations, and it implies that the accretion is highly super-Eddington. With reference to recent simulations, the data suggest that this QSO is emitting close to its radiative limit in a regime where strong outflows are expected around a polar conical region.

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Journal
Astronomy and Astrophysics
Published
2025-12-22
DOI
https://doi.org/10.1051/0004-6361/202557285
Citations
4
Primary Topic
Astrophysical Phenomena and Observations
Type
article
Field-Weighted Citation Impact
4.62

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article

Spatially resolved broad-line region in a quasar at z = 4

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Astronomy and Astrophysics
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Spatially resolved broad-line region in a quasar at z = 4

D. Santos, M. Subroweit, C. Straubmeier, X. Haubois, S. Lacour, Frédéric Gonté, J. Woillez, Christian Rau, R. Laugier, Nuno Morujão, S. Gillessen, K. Perraut, L. C. Ho, S. Robbe-Dubois, C. Wolf, M. Houllé, Carlos M. Correia, Gerhard Ulbricht, Sylvain Oberti, Simran Joharle, Michael Hartl, Pavel Shchekaturov, F. Vincent, J. Shangguan, Alejandro Farah, T. Ott, Anthony Berdeu, Laura Kreidberg, R. Davies, L. J. Tacconi, Rachel Webster, N. Pourré, A. Drescher, H. Nowacki, Ferréol Soulez, D. Defrère, Nikhil More, J. Kolb, C. Sykes, G. Bourdarot, F. Haußmann, A. Eckart, A. Mérand, H. Feuchtgruber, G. Perrin, Maximilian Fabricius, D. Lutz, P. Bourget, D. Ribeiro, A. Labdon, R. Petrov, R. Genzel, Thomas Shimizu, W. Brandner, Christopher A. Onken, Samuel Lai, Olivier Lai, J. Leftley, H. Übler, F. Millour, Muhammad Salman, J. Sauter, M. Scialpi, F. Eisenhauer, Carolina Keiman, P. García, A. Foschi, Salvador Cuevas Cardona, N. Aimar, J. Osorno, R. García López, M. Montargès, J. Scigliuto, Rui Li, Tiago Gomes, T. Paumard, N. M. Förster Schreiber, Yixian Cao, J. Sánchez-Bermúdez, M. Sadun Bordoni, S. F. Hönig, F. Mang, E. Sturm, P. Kervella, M. Nowak, B. López, S. Rabien, E. Wieprecht, K. El Dayem, V. Gopinath, J. Graf
article en
4 citations

Abstract

We present the first near-infrared interferometric data of a QSO at z = 4. The K -band observations were performed with GRAVITY+ on the VLTI using all four UTs, detecting a differential phase signal that traces the spatially resolved kinematics for both the H β and H γ lines in the broad-line region (BLR). We fit the two lines simultaneously with an updated model that includes distinct rotating and conical outflowing components. For the best-fit model, more than 80% of the H I line emission from the BLR originates in an outflow with a velocity up to 10 4 km s −1 . This is oriented so that our line of sight is along an edge of the conical structure, which produces the prominent blue wing on the line profile. A combination of anisotropic line emission and mid-plane opacity leads to the single-sided phase signal. The model is able to qualitatively match both the outflowing C IV line profile and the systemic O I fluorescent emission. The black hole mass of 8 × 10 8 M ⊙ that we derive is the highest redshift black hole mass measurement to date obtained directly from BLR dynamics. It is an order of magnitude lower than that inferred from various single epoch scaling relations, and it implies that the accretion is highly super-Eddington. With reference to recent simulations, the data suggest that this QSO is emitting close to its radiative limit in a regime where strong outflows are expected around a polar conical region.

Astronomy and AstrophysicsVol. 706
Université Claude Bernard Lyon 1 (FR), University College Dublin (IE), King University (US), École Normale Supérieure de Lyon (FR), Australian National University (AU), Centre National de la Recherche Scientifique (FR), Dublin Institute For Advanced Studies (IE), The University of Melbourne (AU), Lyon College (US), University of Cologne (DE), Universidade do Porto (PT), Peking University (CN), Université Paris Cité (FR), Arcetri Astrophysical Observatory (IT), Sorbonne Université (FR), Institute of Astrophysics and Space Sciences (PT), Sorbonne Paris Cité (FR), Max Planck Institute for Extraterrestrial Physics (DE), Max Planck Institute for Astronomy (DE), Institute of Astronomy (RU), Observatoire de la Côte d’Azur (FR), ARC Centre of Excellence for Gravitational Wave Discovery (AU), Astronomy and Space (AU), Max Planck Institute for Radio Astronomy (DE), University of Southampton (GB), Technical University of Munich (DE), Universidad Nacional Autónoma de México (MX), Université Grenoble Alpes (FR), KU Leuven (BE)
National Science Foundation, Government of the United Kingdom, UK Research and Innovation, University of Southampton, Commonwealth Scientific and Industrial Research Organisation, University College Dublin, Agence Nationale de la Recherche, National Natural Science Foundation of China, KU Leuven, European Southern Observatory, Centre National de la Recherche Scientifique, Universidad Nacional Autónoma de México, Universidade de Lisboa, Peking University, Universität zu Köln, Max-Planck-Institut für Astronomie, Observatoire de Paris, Université de Recherche Paris Sciences et Lettres, HORIZON EUROPE Framework Programme, Science and Technology Facilities Council, Fundação para a Ciência e a Tecnologia, Dirección General de Asuntos del Personal Académico, Universidad Nacional Autónoma de México, Fundamental Research Funds for the Central Universities
Openalex Percentile: Top 5%
Astrophysical Phenomena and Observations
4.62
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