Joint Astrophysical Colloquium
High-resolution spectroscopy of ultra-fast outflows from supermassive black holes with XRISM
Kouichi Hagino (University of Tokyo)
Thursday 02/07/2026 @ 11:30, Sala Antonio Sollima (IV piano Battiferro)
Ultra-fast outflows (UFOs) are the fastest accretion-disk winds launched from supermassive black holes (SMBHs), with typical velocities of 0.1-0.3c. They are commonly observed as blue-shifted Fe XXV and/or Fe XXVI absorption lines at X-ray energies of 7-10 keV. Because of their extreme velocities, UFOs are considered one of the most promising channels transferring kinetic energy from SMBHs to their host galaxies, potentially driving the co-evolution of black holes and galaxies. Since its launch in 2023, the X-Ray Imaging and Spectroscopy Mission (XRISM) has been revolutionizing UFO studies with its unprecedented spectral resolution. In this presentation, I will highlight recent XRISM observations of UFOs, focusing on the discovery of their complex internal structures and discussing the implications for their energetics, feedback efficiency, and driving mechanisms.