The impact of feedback from galaxy formation on cosmological probes is typically quantified in terms of the suppression of the matter power spectrum in hydrodynamical compared to gravity-only simulations. In this paper, we instead study how baryonic feedback impacts halo assembly histories and thereby imprints on cosmological observables. We investigate the sensitivity of the thermal Sunyaev-Zel’dovich effect (tSZ) power spectrum, X-ray number counts, weak lensing and kinetic Sunyaev-Zel’dovich (kSZ) stacked profiles to halo populations as a function of mass and redshift. We then study the imprint of different feedback implementations in the FLAMINGO suite of cosmological simulations on the assembly histories of these halo populations, as a function of radial scale. We find that kSZ profiles target lower-mass halos (M200 m∼1013.1M⊙) compared to all other probes considered (M200 m∼1015M⊙). Feedback is inefficient in high-mass clusters with ∼1015M⊙ at z=0, but was more efficient at earlier times in the same population, with a ∼5–10% effect on mass at 2z4 (depending on radial scale). Conversely, for lower-mass halos with ∼1013M⊙ at z=0, feedback exhibits a ∼5–20% effect on mass at z=0 but had little impact at earlier times (z>2). These findings are tied together by noting that, regardless of redshift, feedback most efficiently redistributes baryons when halos reach a mass of M200 m≃1012.8M⊙ and ceases to have any significant effect by the time M200 m≃1015M⊙. We put forward strategies for minimizing sensitivity of lensing analyses to baryonic feedback, and for exploring baryonic resolutions to the unexpectedly low tSZ power in cosmic microwave background observations.
Lucie-Smith et al. (2025) studied this question.