Probing hot gas around luminous red galaxies through the Sunyaev-Zel'dovich effect

Understand

We construct the mean thermal Sunyaev-Zel'dovich (tSZ) Comptonization y profile around Luminous Red Galaxies (LRGs) in the redshift range 0.16 < z < 0.47 from the Sloan Digital Sky Survey (SDSS) Data Release 7 (DR7) using the Planck y map.

• The mean central tSZ signal for the full sample is y ~ 1.8 * 10^(-7) and we detect tSZ emission out to ~30 arcmin, which is well beyond the 10 arcmin angular resolution of the y map and well beyond the virial radii of the LRGs.
• We compare the measured profile with predictions from the cosmo-OWLS suite of cosmological hydrodynamical simulations.
• This comparison agrees well for models that include feedback from active galactic nuclei (AGN), but not with hydrodynamic models without this energetic feedback mechanism.