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Lookup NU author(s): Dr Tiago CostaORCiD
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
© 2026. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.We present a systematic study of the environments of 25 luminous quasars at z > 6.5 from the ASPIRE program. Using JWST/NIRCam wide-field slitless spectroscopy data, we identified 487 galaxies at 5.3 ≲ z ≲ 7.0 exhibiting [O iii] emission. Among these, 122 [O iii] emitters lie within ∣Δvlos∣ < 1000 km s−1 of the quasars, corresponding to a ∼9.4-fold enhancement relative to the average galaxy density at other redshifts. Furthermore, we identified 16 [C ii]-emitting galaxies at the quasar redshifts from Atacama Large Millimeter/submillimeter Array (ALMA) mosaic observations. A cross-correlation function analysis between quasars and [O iii]+[C ii] emitters yields a cross-correlation length of (Formula presented) r0QG=8.68−0.55+0.51h−1cMpc and an autocorrelation of (Formula presented) r0QQ=15.76−2.70+2.48h−1cMpc, indicating that z ∼ 7 quasars reside in dark matter halos with (Formula presented) Mhalo=1012.27−0.26+0.21M⊙ and have a quasar lifetime of (Formula presented) tQ=107.05−1.01+0.95yr. Notably, the number of [O iii]-emitting galaxies at quasar redshifts varies significantly from field to field, ranging from 0 to 20, highlighting a diverse quasar environment. Remarkably, seven quasars trace significant galaxy overdensities (i.e., protoclusters), with δgal > 5 within a volume of V ∼ 500 cMpc3. We also find that ∣Δvlos∣ increases rapidly toward smaller galaxy–quasar separations in protocluster fields, consistent with galaxy kinematics around extremely massive halos in cosmological simulations. By combining JWST and ALMA data, we reveal the complex and diverse environments of these early quasars, providing robust evidence that the earliest luminous quasars are effective tracers of galaxy overdensities, albeit with substantial field-to-field variation.
Author(s): Wang F, Champagne JB, Huang J, Yang J, Hennawi JF, Fan X, Zhang H, Costa T, Decarli R, Habouzit M, Sun F, Banados E, Jin X, Kakiichi K, Meyer RA, Wu Y, Belladitta S, Blecha L, Bosman SEI, Cai Z, Connor T, Davies FB, Eilers A-C, Haiman Z, Jun HD, Li M, Li Z, Liu W, Lupi A, Lyu J, Mazzucchelli C, Onoue M, Pizzati E, Pudoka M, Rojas-Ruiz S, Schindler J-T, Shen Y, Tee WL, Trakhtenbrot B, Trebitsch M, Vestergaard M, Volonteri M, Walter F, Zhang H, Zou S
Publication type: Article
Publication status: Published
Journal: Astrophysical Journal
Year: 2026
Volume: 1006
Issue: 1
Online publication date: 13/07/2026
Acceptance date: 09/06/2026
Date deposited: 20/07/2026
ISSN (print): 0004-637X
ISSN (electronic): 1538-4357
Publisher: American Astronomical Society
URL: https://doi.org/10.3847/1538-4357/ae7bfa
DOI: 10.3847/1538-4357/ae7bfa
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