Cosmological feedback from a halo assembly perspective
Luisa Lucie-Smith, Hiranya V. Peiris, Andrew Pontzen, Anik Halder, Joop Schaye, Matthieu Schaller, John Helly, Robert J. McGibbon, Willem Elbers
arXiv:2505.18258v1 Announce Type: new
Abstract: 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 ($M_{rm 200m}sim 10^{13.1},mathrm{M}_odot$) compared to all other probes considered ($M_{200mathrm{m}}sim 10^{15},mathrm{M}_odot$). Feedback is inefficient in high-mass clusters with $sim 10^{15} , mathrm{M}_odot$ at $z=0$, but was more efficient at earlier times in the same population, with a $sim 5$-$10%$ effect on mass at $22$). These findings are tied together by noting that, regardless of redshift, feedback most efficiently redistributes baryons when halos reach a mass of $M_{rm 200m} simeq {10^{12.8}},mathrm{M}_{odot}$ and ceases to have any significant effect by the time $M_{rm 200m} simeq {10^{15}},mathrm{M}_{odot}$. 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.arXiv:2505.18258v1 Announce Type: new
Abstract: 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 ($M_{rm 200m}sim 10^{13.1},mathrm{M}_odot$) compared to all other probes considered ($M_{200mathrm{m}}sim 10^{15},mathrm{M}_odot$). Feedback is inefficient in high-mass clusters with $sim 10^{15} , mathrm{M}_odot$ at $z=0$, but was more efficient at earlier times in the same population, with a $sim 5$-$10%$ effect on mass at $22$). These findings are tied together by noting that, regardless of redshift, feedback most efficiently redistributes baryons when halos reach a mass of $M_{rm 200m} simeq {10^{12.8}},mathrm{M}_{odot}$ and ceases to have any significant effect by the time $M_{rm 200m} simeq {10^{15}},mathrm{M}_{odot}$. 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.