SEARCHING for FOSSIL EVIDENCE of AGN FEEDBACK in WISE-SELECTED STRIPE-82 GALAXIES by MEASURING the THERMAL SUNYAEV-ZEL'DOVICH EFFECT with the ATACAMA COSMOLOGY TELESCOPE

We directly measure the thermal energy of the gas surrounding galaxies through the thermal Sunyaev-Zel'dovich (tSZ) effect. We perform a stacking analysis of microwave background images from the Atacama Cosmology Telescope, around 1179 massive quiescent elliptical galaxies at 0.5 ≤ z ≤ 1.0 ("low-z") and 3274 galaxies at 1.0 ≤ z ≤ 1.5 ("high-z"), selected using data from the Wide-field Infrared Survey Explorer All-Sky Survey and the Sloan Digital Sky Survey (SDSS) within the SDSS Stripe-82 field. The gas surrounding these galaxies is expected to contain energy from past episodes of active galactic nucleus (AGN) feedback, and after using modeling to subtract undetected contaminants, we detect a tSZ signal at a significance of for our low-z galaxies and for our high-z galaxies. We then include data from the high-frequency Planck bands for a subset of 227 low-z galaxies and 529 high-z galaxies and find low-z and high-z tSZ detections of and , respectively. These results indicate an average thermal heating around these galaxies of erg for our low-z galaxies and erg for our high-z galaxies. Based on simple heating models, these results are consistent with gravitational heating without additional heating due to AGN feedback.