Using Real and Simulated Measurements of the Thermal Sunyaev-Zel'dovich
  Effect to Constrain Models of AGN Feedback
  Energetic feedback from active galactic nuclei (AGNs) is often used in
simulations to resolve several outstanding issues in galaxy formation, but its
impact is still not fully understood. Here we derive new constraints on AGN
feedback by comparing observations and simulations of the thermal
Sunyaev-Zel'dovich (tSZ) effect. We draw on observational results presented in
Spacek et al. (2016, 2017) who used data from the South Pole Telescope (SPT)
and Atacama Cosmology Telescope (ACT) to measure the tSZ signal from >= 10^11
M_Sun and >= 1 Gyr galaxies at z=0.5-1.0 (low-z) and z=1.0-1.5 (high-z). Using
the large-scale cosmological hydrodynamical simulations Horizon-AGN and
Horizon-NoAGN, which include and omit AGN feedback, we extract simulated tSZ
measurements around galaxies equivalent to the observational work. We find that
the Horizon-AGN results only differ from the SPT measurements at levels of 0.4
sigma (low-z) and 0.6 sigma (high-z), but differ from the ACT measurements by
3.4 sigma (low-z) and 2.3 sigma (high-z). The Horizon-NoAGN results provide a
slightly better fit to the SPT measurements by differing by 0.2 sigma (low-z)
and 0.4 sigma (high-z), but a significantly better match to the ACT
measurements by differing by only 0.5 sigma (low-z) and 1.4 sigma (high-z). We
conclude that, while the lower-mass (<~ 5 x 10^11 M_Sun) SPT results allow for
the presence AGN feedback energy, the higher-mass (>~ 5 x 10^11 M_Sun) ACT
results show significantly less energy than predicted in the simulation
including AGN feedback, while more closely matching the simulation without AGN
feedback, indicating that AGN feedback may be milder than often predicted in
simulations.
