Clustering of z~6.6 Quasars and [O III] Emitters Constrains Host Halo Masses and Duty Cycles in 25 ASPIRE Fields

TL;DR

This study combines JWST ASPIRE WFSS measurements of the auto-correlation of [O III] emitters and the cross-correlation with z~6 quasars across 25 fields to constrain the typical host halo masses and quasar duty cycles at $z\sim6.6$. By forward-modeling the selection function with FLAMINGO-10k mocks and constructing a mass-dependent covariance matrix, the authors perform a joint inference of the minimum halo masses $M_h^{\rm [OIII]}$ and $M_h^{\rm QSO}$ via a likelihood framework that accounts for cosmic variance and bin correlations. They find $\log M_h^{\rm [OIII]}/M_\odot = 10.55^{+0.11}_{-0.12}$ and $\log M_h^{\rm QSO}/M_\odot = 12.13^{+0.31}_{-0.38}$, with duty cycles $f^{\rm [OIII]}_{\rm duty} = 2.5^{+1.3}_{-0.8}\%$ and $f^{\rm QSO}_{\rm duty} = 0.3^{+4.8}_{-0.3}\%$, implying UV-bright phases are brief and contribute modestly to SMBH growth. The results, consistent with a small UV-luminous epoch, support scenarios where substantial SMBH mass assembly occurs in obscured or radiatively inefficient phases. The methodological core—simulation-based covariance and forward-modeled selection—demonstrates a robust path for high-redshift clustering analyses with upcoming wide-field JWST and future Euclid/Roman data.

Abstract

We use data from the JWST ASPIRE Wide Field Slitless Spectroscopy (WFSS) program to measure the auto-correlation function of [O,{\sc iii}] emitters at 5.3$<z<$7.0 and the quasar--[O,{\sc iii}] emitter cross-correlation around 25 ASPIRE quasars (6.51$<z<$6.82; $\langle z\rangle=6.6$). We use synthetic source injection to calibrate the selection function, which we combine with the large-volume FLAMINGO-10k simulation (2.8,cGpc box) to construct realistic mock observations. Our simulation-based approach captures nonlinear structure growth and scale-dependent bias on small scales and derives covariance matrices that include cosmic variance. The clustering yields correlation lengths of $r_0^{\rm GG}=4.7^{+0.4}{-0.5},h^{-1}$,cMpc for the [O,{\sc iii}] auto-correlation with fixed slope $γ{\rm GG}=1.8$, and $r_0^{\rm QG}=8.7^{+0.8}{-0.9},h^{-1}$,cMpc for the quasar--[O,{\sc iii}] cross-correlation with $γ{\rm QG}=2.0$. We infer $\log(M_{h,{\rm min}}^{[{\rm O,III}]}/M_\odot)=10.5^{+0.1}{-0.1}$ for [O,{\sc iii}] emitters and $\log(M{h,{\rm min}}^{\rm QSO}/M_\odot)=12.1^{+0.3}{-0.4}$ for quasars. These imply duty cycles of $2.5^{+1.0}{-0.8}$,per,cent for [O,{\sc iii}] emitters and $0.3^{+4.0}{-0.3}$,per,cent for quasars, corresponding to UV-bright lifetimes of $t{\rm Q}=2.6^{+30}_{-2.5}$,Myr (less than 10,per,cent of a Salpeter $e$-folding time). The results indicate that the observed UV-luminous phase contributes little to total SMBH growth, placing tight constraints on early black-hole formation.

Figures (14)

• Figure 1: Two examples of the sensitivity map for quasar field J0109-3047 and J0224-4711, the orange stars mark the location of the quasars. Each pixel value (Flim) on the sensitivity map is computed from the S/N of the injected source. The inject mock grid has size 40 rows $\times$ 25 columns, and the direction of the columns follows the direction of the dispersion. Grid points with no detection (i.e., the redshift of the mock source is misidentified with $|z-z_{\rm true}|>0.01$), where $z_{\rm true}=6.5$ for the injected mocks, are shown in pink. In the left panel, we mark the dispersion direction of Grism R (dispersion across detector rows) as red arrows for modules A and B. The color bars correspond to the $5\sigma$ flux limit, where deeper bluer color means more sensitive to the faint sources. The vertical stripes of non-detection within the FOV correspond to the contamination due to the dispersed foreground bright sources.
• Figure 2: The spatial coverage map of quasar field J0109-3047 ($z_{\rm QSO}=6.79$) for 9 example redshifts between $z=5.3$ (blue) to $7.0$ (red). The colored grid points show the region where covered=True.
• Figure 3: Correlation matrices of the volume-averaged correlation functions, normalized by their diagonal elements. The left panel shows the auto-correlation function of [O iii] emitters, $\chi_{\rm GG}$, and the right panel shows the quasar–[O iii] cross-correlation function, $\chi_{\rm QG}$. Both are computed using Eq. \ref{['eq:covariance']} based on 1,000 mock realizations generated for the minimum-mass model with $\log(M_h^{\rm gal}/M_\odot)=10.6$ and $\log(M_h^{\rm QSO}/M_\odot)=12.2$, where one mock realization computes the correlation functions based on the total number counts across all 25 ASPIRE-like quasar fields. The tick labels on each axis indicate the bin centers for the projected-radius, $r_p^{\rm center}$. The off-diagonal structure reflects correlated uncertainties arising from pair-count covariance and large-scale structure modes coupling across bins.
• Figure 4: Power law fit to the volume averaged [O iii]-emitter auto correlation function (red) and the quasar--[O iii]-emitter cross correlation function (blue). The fit assumes the powerlaw index for the 2d correlation function, $\gamma_{\rm QG}=2.0$ and $\gamma_{\rm GG}=1.8$. For each case, we sample the posterior distribution of the correlation length $r_0$, and show the median model (solid line) along with the $1\sigma$ credible interval (shaded region).
• Figure 5: MCMC Posterior distribution joint power law model fit to the ASPIRE [O iii]-emitter auto correlation function and quasar-[O iii]-emitter cross correlation with fixed power law index $\gamma_{\rm QQ}=2$ and $\gamma_{\rm GG}=1.8$. The likelihood function is given by Eq. \ref{['eq:total_likelihood']}. The 16-84th percentile range in the marginalized posterior is shown with vertical dashed lines.