Joint X-ray, kinetic Sunyaev-Zeldovich, and weak lensing measurements: toward a consensus picture of efficient gas expulsion from groups and clusters

TL;DR

This study combines X-ray, kSZ, and lensing data to investigate baryon feedback in galaxy groups and clusters, revealing more efficient gas expulsion than current simulations predict, impacting matter distribution models.

Contribution

It provides the first joint analysis of these measurements across various halo masses and redshifts, highlighting discrepancies with state-of-the-art simulations and suggesting more powerful AGN outbursts.

Findings

eROSITA X-ray gas fractions are twice lower than simulations

kSZ measurements are over 8 sigma discrepant with models

Enhanced gas expulsion aligns with a more suppressed matter power spectrum

Abstract

There is no consensus on how baryon feedback shapes the underlying matter distribution from either simulations or observations. We confront the uncertain landscape by jointly analyzing new measurements of the gas distribution around groups and clusters -- DESI+ACT kinetic Sunyaev-Zel'dovich (kSZ) effect profiles and eROSITA X-ray gas masses -- with mean halo masses characterized by galaxy-galaxy lensing. Across a wide range of halo masses ($M_{500}=10^{13-14}M_\odot$) and redshifts ($0<z<1$), we find evidence of more efficient gas expulsion beyond several $R_{500}$ than predicted by most state-of-the-art simulations. A like-with-like comparison reveals all kSZ and X-ray observations are inconsistent with the fiducial 1 Gpc$^{3}$ hydrodynamical FLAMINGO simulation, which was calibrated to reproduce pre-eROSITA X-ray gas fractions: eROSITA X-ray gas fractions are $2\times$ lower than the simulation, and the kSZ measurements are combined $>8 \sigma$ discrepant. The FLAMINGO simulation variant with the most gas expulsion, and therefore the most suppression of the matter power spectrum relative to a dark matter only simulation, provides a good description of how much gas is expelled and how far it extends; the enhanced gas depletion is achieved by more powerful but less frequent AGN outbursts. Joint kSZ, X-ray, and lensing measurements form a consistent picture of gas expulsion beyond several $R_{500}$, implying a more suppressed matter power spectrum than predicted by most recent simulations. Complementary observables and next-generation simulations are critical to understanding the physical mechanism behind this extreme gas expulsion and mapping its impact on the large-scale matter distribution.