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Abstract Quasar feedback is a key ingredient in shaping galaxy evolution. A rare population of extremely red quasars (ERQs) atz= 2−3 are often associated with high-velocity [Oiii]λ5008 outflows and may represent sites of strong feedback. In this paper, we present an X-ray study of 50 ERQs to investigate the link between the X-ray and outflow properties of these intriguing objects. Using hardness ratio analysis, we confirm that the ERQs are heavily obscured systems with gas column density reachingN_H= 10²³⁻²⁴cm⁻². We identify 20 X-ray-nondetected ERQs at high mid-infrared (MIR) luminosities ofνL_ν,6μm≳ 3 × 10⁴⁶erg s⁻¹. By stacking the X-ray observations, we find that the nondetected ERQs are on average underluminous in X-rays by a factor of ∼10 for their MIR luminosities. We consider such X-ray weakness to be due to both heavy gas absorption and intrinsic factors. Moreover, we find that the X-ray-weak sources also display higher-velocity outflows. One option to explain this trend is that weaker X-rays facilitate more vigorous line-driven winds, which then accelerate the [Oiii]-emitting gas to kiloparsec scales. Alternatively, super-Eddington accretion could also lead to intrinsic X-ray weakness and more powerful continuum-driven outflow. 

Abstract Dual quasars—two active supermassive black holes at galactic scales—represent crucial objects for studying the impact of galaxy mergers and quasar activity on the star formation rate (SFR) within their host galaxies, particularly at cosmic noon when SFR peaks. We present JWST/MIRI mid-infrared integral field spectroscopy of J074922.96+225511.7, a dual quasar with a projected separation of 3.8 kpc at a redshiftz= 2.17. We detect spatially extended [Feii] 5.34μm and polycyclic aromatic hydrocarbon (PAH) 3.3μm emissions from the star formation activity in its host galaxy. We derive the SFR of 10^3.0±0.2M_⊙yr⁻¹using PAH 3.3μm, which is 5 times higher than that derived from the knee of the infrared luminosity function for galaxies atz∼ 2. While the SFR of J0749+2255 agrees with that of star-forming galaxies of comparable stellar mass at the same redshifts, its molecular gas content falls short of expectations based on the molecular Kennicutt–Schmidt law. This discrepancy may result from molecular gas depletion due to the longer elevated stage of star formation, even after the molecular gas reservoir is depleted. We do not observe any quasar-driven outflow that impacts PAH and [Feii] in the host galaxy based on the spatially resolved maps. From the expected flux in PAH-based star formation, the [Feii] line likely originates from the star-forming regions in the host galaxy. Our study highlights the extreme stardust nature of J0749+2255, indicating a potential connection between the dual quasar phase and intense star formation activities.