The WISSHFUL program: the highest redshift UFO discovered in a non-lensed QSO

We present the first results from the WISSHFUL program, an XMM-Newton heritage program targeting luminous QSOs at Cosmic Noon. We report on recent simultaneous XMM-Newton and NuSTAR observations of the Super-Eddington accreting quasar WISSH13 at z=3.294, which provide the highest quality broadband X-ray spectrum to date for a non-lensed QSO at this redshift. Physical modeling of the continuum reveals a soft photon index (Γ∼2) and strong reflection (R∼1.4−1.8), despite the weak narrow Fe emission, and a low high-energy cut-off (Ecut∼60−80 keV, kTe=15−20 keV, depending on the model adopted). Most notably, we detect two significant (at 96.7% and 98.9% confidence level, respectively) absorption features at ∼7.5 and ∼10 keV rest-frame, interpreted as a blueshifted blend of Fe XXV Heα and Fe XXVI Lyα. These features indicate the presence of two kinematic components of a highly ionized, high column Ultra-Fast Outflow (UFO) with a velocity of vout∼0.1c and vout∼0.3c, respectively. The slower wind is consistently detected in an archival 2017 XMM-Newton observation, whereas the faster wind is detected only in 2024. This stratified and variable wind exhibits extreme energetics, with a mass outflow rate of M˙out∼20M⊙/yr (corresponding to 15%M˙acc) for each component, and a kinetic power of the order of ∼1 and ∼10% of the bolometric luminosity, respectively. While this represents one of the most powerful UFOs ever detected, its kinetic power is a similar fraction of the QSO's bolometric luminosity compared to lower-redshift AGN. We present several theoretical frameworks to explain the peculiar accretion and ejection properties of this remarkable QSO at Cosmic Noon.