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

TL;DR

This study measures the thermal energy around galaxies using the tSZ effect to investigate potential AGN feedback, finding results consistent with gravitational heating alone.

Contribution

It provides the first direct measurements of gas thermal energy around galaxies at different redshifts using stacking of microwave background data, testing AGN feedback models.

Findings

Detected tSZ signals at 0.9-1.8 sigma significance levels.

Estimated thermal energies consistent with gravitational heating.

No strong evidence for additional AGN feedback heating.

Abstract

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 0.9-sigma for our low-z galaxies and 1.8-sigma 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 1.0-sigma and 1.5-sigma, respectively. These results indicate an average thermal heating around these galaxies of 5.6(+5.9/-5.6) x 10^60 erg for our low-z galaxies and 7.0(+4.7/-4.4) x 10^60 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.