Disentangling multiple gas kinematic drivers in the Perseus galaxy cluster
Summary
The XRISM Collaboration uses high-resolution X-ray spectroscopy from the Resolve instrument to map line-of-sight (LOS) gas velocities and velocity dispersions across the core of the Perseus galaxy cluster. By combining XRISM Resolve observations with Chandra imaging and tailored numerical simulations (including sloshing and AGN jet feedback), the team separates the contributions of large-scale sloshing, AGN-driven turbulence and waves, and other motions to the observed gas kinematics. The study compares results with earlier Hitomi and Chandra work and explores implications for intracluster medium (ICM) heating and cooling.
Key Points
- XRISM Resolve provides spatially resolved measurements of LOS bulk velocity and velocity dispersion across the Perseus core, improving on previous instruments.
- Observations show a mix of coherent bulk flows (consistent with sloshing) and enhanced central velocity dispersion (linked to AGN activity and small-scale turbulence).
- Tailored hydrodynamic simulations (FLASH and AREPO branches with custom AGN implementations) are used to model sloshing and jet-driven turbulence and to interpret the XRISM maps.
- The work disentangles kinematic drivers by comparing emissivity-weighted simulated profiles with XRISM data, constraining the relative roles of sloshing, AGN bubbles, and sound waves in transporting energy.
- Data and many analysis tools are publicly available (XRISM and Chandra IDs, AtomDB, FLASH, AREPO public releases), though a custom AREPO branch used here may be available on request from the developer.
- Results have consequences for understanding ICM heating: both AGN feedback and cluster-scale motions contribute to preventing runaway cooling, but at different spatial scales and with different signatures.
- This is a large, multi-institution collaboration (the XRISM Collaboration) and connects XRISM first-light science to a broad body of previous observational and theoretical work (Hitomi, Chandra, XMM-Newton, LOFAR and many simulation studies).
Content summary
Using XRISM Resolve observations (five XRISM pointings) together with archival Chandra data, the authors produced velocity and velocity-dispersion maps of Perseus’s core region. Spectral decomposition separated the ICM emission from the central AGN and instrumental/background components. The maps reveal azimuthal and radial variations: large-scale ordered flows consistent with sloshing cold fronts, and a centrally concentrated increase in velocity dispersion associated with AGN-driven processes. The team ran controlled numerical experiments (stratified turbulence, sloshing-only runs, and sloshing+AGN jets) to reproduce the observed profiles and isolate which phenomena dominate at different radii and spatial scales. They also considered sound-wave propagation models and resonant scattering diagnostics to further constrain the energy transport mechanisms. The paper provides data and code availability notes, extensive references, and detailed acknowledgements for the many contributors and funding sources.
Context and relevance
This study builds on Hitomi’s pioneering microcalorimeter spectroscopy and Chandra’s imaging to deliver the next step in spatially resolved ICM kinematics. Separating sloshing, AGN jets/bubbles and turbulent motions is essential for quantifying how energy from a central black hole is distributed through a cluster core and how cooling is regulated. The approach—combining XRISM’s spectral fidelity with high-resolution imaging and bespoke simulations—sets a template for future studies of feedback, turbulence, and ICM microphysics in other clusters. The results are relevant to researchers modelling cluster thermodynamics, AGN feedback, and to observers planning XRISM/Resolve follow-ups or complementary radio and optical campaigns.
Why should I read this
Want the short version? XRISM actually maps how gas moves in the heart of Perseus and, crucially, teases apart who’s doing what — big sloshing motions or the central AGN. If you care about how black holes heat cluster gas (or just want to avoid wading through technical detail), this paper gives clear, measured answers and backs them up with simulations. It’s a solid read if you want to know how clusters stay hot.
Author style
Punchy: this is observational astrophysics at scale — high-precision spectroscopy plus targeted simulations that materially advance our ability to assign observed motions to physical drivers. If you work on cluster physics or AGN feedback, the methods and constraints here are well worth digging into.
Source
Article Date: 28 January 2026
Article URL: https://www.nature.com/articles/s41586-025-10017-x
Article Image: (not provided)