Speaker
Description
We present the latest development of "Baryon Pasting", a novel framework that adopts a physics-based approach for forward-modeling SZ and X-ray observations of galaxy clusters and groups. Baryon Pasting enables efficient exploration of the vast astrophysical and cosmological parameter space required for current and upcoming millimeter-wave surveys, such as the Simons Observatory and CMB-S4, while maintaining the physical accuracy of modern hydrodynamical simulations. This makes Baryon Pasting particularly powerful for disentangling the impact of cluster and group astrophysics from cosmology. Using the half-sky Baryon Pasted Uchuu lightcone simulation, we demonstrate significant map-level systematic effects that were previously difficult to quantify. Application of the Baryon Pasting model to the eRASS1 X-ray angular power spectrum has also yielded precise cosmological constraints, shedding new light on the ongoing S8 tension, as well as constraints on cluster astrophysics of feedback, non-thermal pressure, and the accretion shock radius. We also introduce a differentiable model of Baryon Pasting that captures the effect of halo mass accretion histories on the properties of the intracluster medium and their distinctive observational signatures in X-ray and SZ, such as assembly bias in the X-ray and SZ angular power spectra. Finally, we discuss how integrating Baryon Pasting with state-of-the-art cosmological simulations and cutting-edge generative AI models will fully unlock the potential of next-generation multiwavelength Stage IV surveys through efficient and interpretable modeling of the observable universe.
