Distinguishing AGN Feedback Models with the Thermal Sunyaev-Zel'dovich Effect

TL;DR

This study uses cosmological simulations and tSZ measurements to evaluate different AGN feedback models, demonstrating current observations support models with feedback and proposing future high-resolution measurements to distinguish feedback effects.

Contribution

The paper introduces a method to compare AGN feedback models using tSZ signals from simulations and observations, highlighting the potential of future measurements to differentiate feedback mechanisms.

Findings

Current ACT observations at z~1 support models with AGN feedback.

Models without AGN feedback are inconsistent with observed tSZ signals.

Future high-resolution measurements can uniquely identify AGN feedback profiles.

Abstract

Current models of galaxy formation require strong feedback from active galactic nuclei (AGN) to explain the observed lack of star formation in massive galaxies since z~2 but direct evidence of this energy input is limited. We use the SIMBA cosmological galaxy formation simulations to assess the ability of thermal Sunyaev-Zel'dovich (tSZ) measurements to provide such evidence, by mapping the pressure structure of the circumgalactic medium around massive z~0.2-1.5 galaxies. We undertake a stacking approach to calculate the total tSZ signal and its radial profile in simulations with varying assumptions of AGN feedback, and we assess its observability with current and future telescopes. By convolving our predictions with the 2.1' beam of the Atacama Cosmology Telescope (ACT), we show that current observations at z~1 are consistent with SIMBA's fiducial treatment of AGN feedback, and inconsistent with SIMBA models without feedback. At z~0.5, observational signals lie between SIMBA run with and without AGN feedback, suggesting AGN in SIMBA may inject too much energy at late times. By convolving our data with a 9.5'' beam corresponding to the TolTEC camera on the Large Millimeter Telescope Alfonso Serrano (LMT), we predict a unique profile for AGN feedback that can be distinguished with future higher-resolution measurements. Finally, we explore a novel approach to quantify the non-spherically symmetric features surrounding our galaxies by plotting radial profiles representing the component of the stack with m-fold symmetry.