Quasar Radiative Feedback May Suppress Galaxy Growth on Intergalactic Scales at $z = 6.3$

Yongda Zhu, Eiichi Egami, Xiaohui Fan, Fengwu Sun, George D. Becker, Christopher Cain, Huanqing Chen, Anna-Christina Eilers, Yoshinobu Fudamoto, Jakob M. Helton, Xiangyu Jin, Maria Pudoka, Andrew J. Bunker, Zheng Cai, Jaclyn B. Champagne, Zhiyuan Ji, Xiaojing Lin, Weizhe Liu, Hai-Xia Ma, Zheng Ma, Roberto Maiolino, George H. Rieke, Marcia J. Rieke, Pierluigi Rinaldi, Yang Sun, Wei Leong Tee, Feige Wang, Jinyi Yang, Minghao Yue, Junyu Zhang

First listed 2025-08-29 | Last updated 2025-11-19

Abstract

We present observational evidence that intense ionizing radiation from a luminous quasar suppresses nebular emission in nearby galaxies on intergalactic scales at $z=6.3$. Using JWST/NIRCam grism spectroscopy from the SAPPHIRES and EIGER programs, we identify a moderate but statistically significant decline in [O\,\textsc{iii}]\,$\lambda5008$ luminosity relative to the UV continuum ($L_{5008}/L_{1500}$) among galaxies within $\sim$ 7 comoving Mpc (cMpc) of the quasar J0100$+$2802, the most UV-luminous quasar known at this epoch ($M_{1450}=-29.26$). While $L_{1500}$ remains roughly constant with transverse distance, $L_{5008}$ increases significantly, suggesting suppression of very recent star formation toward the quasar. The effect persists after controlling for completeness, local density, and UV luminosity, and correlates with the projected photoionization-rate profile $Γ_{\mathrm{qso}}$. A weaker but directionally consistent suppression in $L_{5008}/L_{1500}$ is also observed along the line of sight. The transverse suppression radius ($\sim$ 7 cMpc) implies a recent radiative episode with a cumulative duration $\sim$ 3.1 Myr, shorter than required for thermal photoheating to dominate and thus more naturally explained by rapid H$_2$ photodissociation and related radiative processes. Environmental effects alone appear insufficient to explain the signal. Our results provide direct, geometry-based constraints on large-scale quasar radiative feedback and recent quasar lifetimes.

Short digest

Using JWST/NIRCam grism WFSS from the SAPPHIRES and EIGER programs, the authors map [O III] emitters around the z=6.3 quasar J0100+2802 and analyze 130 sources to test radiative feedback. They find a clear decline in [O III] λ5008-to-UV luminosity (L5008/L1500) toward the quasar over ~8–10 cMpc: L1500 stays flat with distance while L5008 rises away from the quasar, and the trend tracks the projected photoionization-rate profile Γ_qso, with a weaker but consistent signal along the line of sight. The inferred transverse suppression radius implies a recent radiative episode of ~4.5 Myr, favoring rapid H2 photodissociation over slower thermal photoheating as the mechanism. Environmental effects alone cannot reproduce the signal, offering geometry-based constraints on intergalactic quasar feedback and recent quasar lifetimes.

Key figures to inspect

• Figure 1: Inspect the sky map and LOS inset to see how [O III] emitters near z≈6.3 are distributed around J0100+2802 and how symbol sizes (L5008) vary with distance; note the fore-/background slices for context.
• Figure 2: Check the injection–recovery completeness versus transverse distance (50–60% thresholds) and the L5008/L1500–distance trend; compare the fitted decline with the overplotted Γ_qso profile to gauge the radiative origin of the suppression.
• Figure 3: Compare the near-QSO, foreground, and background slices; the per-slice fits and CDFs show that only the near-QSO sample exhibits depressed L5008/L1500, while the background overdensity has higher ratios (supported by K–S results).
• Figure 4: Contrast L5008/L1500 with local overdensity (negative trend near the QSO vs weak positive in controls) and verify that M1500 shows no distance trend, arguing against environment or UV luminosity as the driver of the suppression.