[Paper Review] Deciphering baryonic feedback with galaxy clusters

C. To, Shivam Pandey+4 more|arXiv (Cornell University)|Jan 31, 2024

Astronomy and Astrophysical Research4 citations

TL;DR

This paper proposes using Sunyaev-Zel'dovich (SZ) effect observations of galaxy clusters—calibrated with weak gravitational lensing—as a precise probe to constrain baryonic feedback effects on cosmic shear. Leveraging hydrodynamic simulations (IllustrisTNG, Magneticum) and a dark matter + baryon (DMB) halo model, it demonstrates that SZ-cluster measurements can isolate baryonic feedback impacts with statistical and systematic errors subdominant to DES-Y3 and LSST-Y1 cosmic shear uncertainties, offering a promising path for joint CMB and lensing surveys to improve cosmological constraints.

ABSTRACT

Upcoming cosmic shear analyses will precisely measure the cosmic matter distribution at low redshifts. At these redshifts, the matter distribution is affected by galaxy formation physics, primarily baryonic feedback from star formation and active galactic nuclei. Employing measurements from the Magneticum and IllustrisTNG simulations and a dark matter + baryon (DMB) halo model, this paper demonstrates that Sunyaev-Zel'dovich (SZ) effect observations of galaxy clusters, whose masses have been calibrated using weak gravitational lensing, can constrain the baryonic impact on cosmic shear with statistical and systematic errors subdominant to the measurement errors of DES-Y3 and LSST-Y1. We further dissect the contributions from different scales and halos with different masses to cosmic shear, highlighting the dominant role of SZ clusters at scales critical for cosmic shear analyses. These findings suggest a promising avenue for future joint analyses of Cosmic Microwave Background (CMB) and lensing surveys.

Motivation & Objective

• To address the challenge of modeling baryonic feedback in cosmic shear analyses, which currently limits cosmological precision due to uncertainties in galaxy formation physics.
• To reduce the degeneracy between cosmological parameters and baryonic feedback effects by introducing an independent observational probe of matter distribution modulation.
• To evaluate whether SZ effect observations of galaxy clusters, when calibrated with weak lensing, can provide robust constraints on baryonic feedback with minimal systematic error.
• To quantify the contribution of different halo masses and spatial scales to cosmic shear, identifying the dominant scales and systems for feedback sensitivity.
• To validate the DMB halo model as an accurate and efficient framework for modeling baryonic feedback effects on non-linear matter clustering.

Proposed method

• The study uses high-resolution hydrodynamic simulations (IllustrisTNG, Magneticum) to model the impact of baryonic feedback on the matter correlation function and power spectrum at z=0.
• It applies a dark matter + baryon (DMB) halo model to fit the simulated matter clustering, enabling efficient modeling of baryonic feedback effects across scales.
• The authors calibrate cluster masses using weak gravitational lensing measurements, ensuring consistency with observed cluster properties in the simulations.
• They compute cosmic shear signals from the simulated matter distributions and compare the resulting shear power spectra with and without baryonic feedback effects.
• They assess the statistical and systematic error budgets of SZ-cluster observations relative to DES-Y3 and LSST-Y1 cosmic shear measurements.
• They decompose the contributions to cosmic shear by halo mass and scale, identifying the dominant regimes where baryonic feedback leaves a measurable imprint.

Experimental results

Research questions

• RQ1 Can SZ effect observations of galaxy clusters, when mass-calibrated via weak lensing, provide a robust and precise constraint on baryonic feedback effects in cosmic shear?
• RQ2 What is the relative contribution of different halo masses and spatial scales to the modulation of cosmic shear by baryonic feedback?
• RQ3 How do the statistical and systematic errors of SZ-cluster measurements compare to the measurement errors of upcoming cosmic shear surveys like DES-Y3 and LSST-Y1?
• RQ4 To what extent does the DMB halo model accurately reproduce the baryonic feedback imprint seen in hydrodynamic simulations?
• RQ5 Can joint CMB and lensing surveys leverage SZ-cluster observations to break degeneracies between cosmological parameters and baryonic feedback models?

Key findings

• SZ effect observations of galaxy clusters, when calibrated with weak lensing, can constrain baryonic feedback effects on cosmic shear with statistical and systematic errors subdominant to the measurement errors of DES-Y3 and LSST-Y1 cosmic shear surveys.
• The DMB halo model fits both the matter correlation function and power spectrum from the Magneticum simulation with high accuracy, validating its use as a predictive framework.
• Baryonic feedback induces two key features in the matter correlation function: a suppression on small scales and a boost in the 1–2 halo transition regime at ~2 h⁻¹ Mpc, which is localized and has minimal impact on large-scale shear signals.
• The modulation of the matter correlation function due to baryonic feedback is highly localized, with changes <1% at r = 8 h⁻¹ Mpc in the most extreme simulation (Illustris), indicating minimal contamination to large-scale shear measurements.
• The DMB halo model outperforms empirical models like HMcode2020 and Amod in capturing the scale-localized nature of baryonic feedback effects, particularly the 1–2 halo transition feature.
• SZ clusters are the dominant contributors to cosmic shear at scales critical for constraining baryonic feedback, making them ideal probes for future joint CMB and lensing analyses.