XRISM Finds 300 km/s Turbulence in H1821+643, Pointing to 1%-10% Quasar Feedback
Updated
Updated · Nature.com · Jul 29
XRISM Finds 300 km/s Turbulence in H1821+643, Pointing to 1%-10% Quasar Feedback
3 articles · Updated · Nature.com · Jul 29
Summary
XRISM measured unusually broad Fe XXV lines in galaxy cluster H1821+643, showing about 300 km/s gas motions in the intracluster medium around its central quasar.
More than 90% of that line emission comes from 20-100 kpc from the center, where the inferred non-thermal energy fraction is 8.4%—well above the roughly 1%-5% seen in other nearby cluster cores.
The team says a quasar-driven shock is the most plausible cause, with turbulence carrying about 4×10^60 erg, exceeding the 3×10^59 erg mechanical energy previously tied to the system's weak jets.
That implies quasar-mode feedback beyond galactic scales couples at at least 1%-10% efficiency, far above earlier multiwavelength estimates below 0.01% and broadly matching levels used in cosmological simulations.
Because H1821+643 hosts a rare, luminous radio-quiet quasar at z≈0.3 in a massive cluster, the result strengthens the case that quasar winds can regulate galaxy and cluster evolution, not just conditions inside host galaxies.
If black hole winds are 100 times stronger than we thought, what else is hiding in the cosmic dark?
Could the violent storms from a distant black hole rewrite our entire understanding of how galaxies evolve?
Unprecedented Quasar Winds: XRISM’s 2026 Breakthrough and the Cosmic Impact of Supermassive Black Hole Feedback
Overview
In July 2026, the XRISM space telescope revealed that winds from the supermassive black hole in quasar H1821+643 are far more powerful than previously thought. Using XRISM’s advanced Resolve instrument, scientists measured the motion of hot gas around the quasar, finding extreme turbulence that stirs and heats the surrounding intergalactic gas, preventing it from cooling and collapsing. This process, known as quasar-mode feedback, shows how black holes can regulate galaxy growth by expelling gas and altering their environments. The findings highlight the dramatic impact of black hole winds on galaxy evolution and the cosmic landscape.