The suppression of the matter power spectrum: strong feedback from X-ray gas mass fractions, kSZ effect profiles, and galaxy–galaxy lensing

Siegel, J, Bigwood, L, Amon, A, McCullough, J, Yamamoto, M, McCarthy, IG ORCID: 0000-0002-1286-483X, Schaller, M, Schaye, J and Schneider, A (2026) The suppression of the matter power spectrum: strong feedback from X-ray gas mass fractions, kSZ effect profiles, and galaxy–galaxy lensing. Monthly Notices of the Royal Astronomical Society, 549 (4). ISSN 0035-8711

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Abstract

Baryon feedback redistributes gas relative to the underlying dark matter distribution and suppresses the matter power
spectrum on small scales, but the amplitude and scale dependence of this effect are uncertain. We constrain the impact
of baryon feedback on the matter power spectrum by jointly analysing X-ray gas mass fractions from the eROSITA
and HSC–XXL samples and Sloan Digital Sky Survey (SDSS)/Dark Energy Spectroscopic Instrument (DESI) + Atacama
Cosmology Telescope (ACT) kinetic Sunyaev–Zel’dovich (kSZ) effect profiles; the samples are characterized with galaxy–
galaxy lensing and togetherspan group and cluster masses(13 < log10 M500 M h−1 < 14) at 0 < z < 1. Using the baryonification
framework, our joint eROSITA and kSZ model gives precise constraints on the suppression of the matter power spectrum:
10 ± 2 per cent at k = 1 h Mpc−1. The inferred gas profiles are more extended and the power suppression is stronger than
predicted by the fiducial models of recent hydrodynamical simulation suites, including FLAMINGO and BAHAMAS. The
HSC–XXL gas mass fractions, which the fiducial simulations were calibrated to reproduce, prefer more moderate power
suppression than the kSZ and eROSITA data: 5 ± 4 per cent at k = 1 h Mpc−1. With a simulated LSST Year 1 weak lensing
analysis, we demonstrate a framework for next-generation surveys: calibrating feedback models with multiwavelength gas
observables to recover the small-scale statistical power of cosmic shear.

Item Type:	Article
Uncontrolled Keywords:	methods: numerical; galaxies: formation; large-scale structure of Universe; cosmology: theory; astro-ph.CO; astro-ph.CO; 5101 Astronomical Sciences; 51 Physical Sciences; 5107 Particle and High Energy Physics; 51 Physical Sciences; 0201 Astronomical and Space Sciences; Astronomy & Astrophysics; 5101 Astronomical sciences; 5107 Particle and high energy physics; 5109 Space sciences
Subjects:	Q Science > QB Astronomy Q Science > QC Physics
Divisions:	Astrophysics Research Institute
Publisher:	Oxford University Press
Date of acceptance:	29 April 2026
Date of first compliant Open Access:	15 September 2026
Date Deposited:	15 Sep 2026 12:33
Last Modified:	15 Sep 2026 12:33
DOI or ID number:	10.1093/mnras/stag993
URI:	https://researchonline.ljmu.ac.uk/id/eprint/29429

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