article published yes Elia Pizzati author Joseph F. Hennawi author Joop Schaye author Matthieu Schaller author Anna Christina Eilers author Feige Wang author Carlos S. Frenk author Willem Elbers author John C. Helly author Ruari Mackenzie author Jorryt J Matthee author 7439a258-f3c0-11ec-9501-9df22fe067200000-0003-2871-127X Rongmon Bordoloi author Daichi Kashino author Rohan P. Naidu author Minghao Yue author JoMa department Recent observations from the EIGER JWST program have measured for the first time the quasar–galaxy cross-correlation function at z ≈ 6. The autocorrelation function of faint z ≈ 6 quasars was also recently estimated. These measurements provide key insights into the properties of quasars and galaxies at high redshift and their relation with the host dark matter haloes. In this work, we interpret these data building upon an empirical quasar population model that has been applied successfully to quasar clustering and demographic measurements at z ≈ 2–4. We use a new, large-volume N-body simulation with more than a trillion particles, FLAMINGO-10k, to model quasars and galaxies simultaneously. We successfully reproduce observations of z ≈ 6 quasars and galaxies (i.e. their clustering properties and luminosity functions), and infer key quantities such as their luminosity–halo mass relation, the mass function of their host haloes, and their duty cycle/occupation fraction. Our key findings are (i) quasars reside on average in ≈ 1012.5 M haloes (corresponding to ≈ 5σ fluctuations in the initial conditions of the linear density field), but the distribution of host halo masses is quite broad; (ii) the duty cycle of (UV-bright) quasar activity is relatively low (≈ 1 per cent); (iii) galaxies (that are bright in [O III]) live in much smaller haloes (≈ 1010.9 M) and have a larger duty cycle (occupation fraction) of ≈ 13 per cent. Finally, we focus on the inferred properties of quasars and present a homogeneous analysis of their evolution with redshift. The picture that emerges reveals a strong evolution of the host halo mass and duty cycle of quasars at z ≈ 2–6, and calls for new investigations of the role of quasar activity across cosmic time. https://research-explorer.ista.ac.at/download/18523/18542/2024_MonthlyNRoyalAstronSoc_Pizzati.pdf application/pdfno https://creativecommons.org/licenses/by/4.0/ Oxford University Press2024 eng 0035-8711 1365-2966 00133566390000810.1093/mnras/stae2307 53443155-3175 E. Pizzati, J.F. Hennawi, J. Schaye, M. Schaller, A.C. Eilers, F. Wang, C.S. Frenk, W. Elbers, J.C. Helly, R. Mackenzie, J.J. Matthee, R. Bordoloi, D. Kashino, R.P. Naidu, M. Yue, Monthly Notices of the Royal Astronomical Society 534 (2024) 3155–3175. E. Pizzati <i>et al.</i>, “A unified model for the clustering of quasars and galaxies at z ≈ 6,” <i>Monthly Notices of the Royal Astronomical Society</i>, vol. 534, no. 4. Oxford University Press, pp. 3155–3175, 2024. Pizzati, Elia, et al. “A Unified Model for the Clustering of Quasars and Galaxies at z ≈ 6.” <i>Monthly Notices of the Royal Astronomical Society</i>, vol. 534, no. 4, Oxford University Press, 2024, pp. 3155–75, doi:<a href="https://doi.org/10.1093/mnras/stae2307">10.1093/mnras/stae2307</a>. Pizzati E, Hennawi JF, Schaye J, Schaller M, Eilers AC, Wang F, Frenk CS, Elbers W, Helly JC, Mackenzie R, Matthee JJ, Bordoloi R, Kashino D, Naidu RP, Yue M. 2024. A unified model for the clustering of quasars and galaxies at z ≈ 6. Monthly Notices of the Royal Astronomical Society. 534(4), 3155–3175. Pizzati, E., Hennawi, J. F., Schaye, J., Schaller, M., Eilers, A. C., Wang, F., … Yue, M. (2024). A unified model for the clustering of quasars and galaxies at z ≈ 6. <i>Monthly Notices of the Royal Astronomical Society</i>. Oxford University Press. <a href="https://doi.org/10.1093/mnras/stae2307">https://doi.org/10.1093/mnras/stae2307</a> Pizzati, Elia, Joseph F. Hennawi, Joop Schaye, Matthieu Schaller, Anna Christina Eilers, Feige Wang, Carlos S. Frenk, et al. “A Unified Model for the Clustering of Quasars and Galaxies at z ≈ 6.” <i>Monthly Notices of the Royal Astronomical Society</i>. Oxford University Press, 2024. <a href="https://doi.org/10.1093/mnras/stae2307">https://doi.org/10.1093/mnras/stae2307</a>. Pizzati E, Hennawi JF, Schaye J, et al. A unified model for the clustering of quasars and galaxies at z ≈ 6. <i>Monthly Notices of the Royal Astronomical Society</i>. 2024;534(4):3155-3175. doi:<a href="https://doi.org/10.1093/mnras/stae2307">10.1093/mnras/stae2307</a> 185232024-11-10T23:01:58Z2025-09-08T14:40:22Z