Self-consistent secondary cosmic microwave background anisotropies and extragalactic foregrounds in the FLAMINGO simulations

TL;DR

This paper introduces a new set of self-consistent mock CMB maps from FLAMINGO hydrodynamical simulations, capturing secondary anisotropies and foregrounds, and compares them with previous models and observations.

Contribution

The authors develop a comprehensive, self-consistent suite of mock CMB maps from hydrodynamical simulations, improving upon previous dark matter-only models.

Findings

Simulations reproduce a wide range of observational constraints.

Hydrodynamical mocks perform as well as or better than previous models in matching observations.

Predictions show significant differences in cross-correlations depending on cosmology and feedback models.

Abstract

Secondary anisotropies in the cosmic microwave background (CMB) contain information that can be used to test both cosmological models and models of galaxy formation. Starting from lightcone-based HEALPix maps and catalogues, we present a new set of mock CMB maps constructed in a self-consistent manner from the FLAMINGO suite of cosmological hydrodynamical simulations, including CMB lensing, thermal and kinetic Sunyaev-Zeldovich effects, cosmic infrared background, radio point source and anisotropic screening maps. We show that these simulations reproduce a wide range of observational constraints. We also compare our simulations with previous predictions based on dark matter-only simulations which generally model the secondary anisotropies independently from one another, concluding that our hydrodynamical simulation mocks perform at least as well as previous mocks in matching the observations whilst retaining self-consistency in the predictions of the different components. Using the model variations in FLAMINGO, we further explore how the signals depend on cosmology and feedback modelling, and we predict cross-correlations between some of the signals that differ significantly from those in previous mocks. The mock CMB maps should provide a valuable resource for exploring correlations between different secondary anisotropies and other large-scale structure tracers, and can be applied to forecasts for upcoming surveys.