Probing Hot Gas in Galaxy Groups through the Sunyaev-Zeldovich Effect

TL;DR

This paper explores how upcoming Sunyaev-Zeldovich effect surveys can be used to study hot gas in galaxy groups and dark matter halos, providing new methods to constrain gas properties across a range of halo masses.

Contribution

It introduces models and techniques for using SZE data and galaxy surveys to probe hot gas in galaxy groups and dark halos, including stacking and cross-correlation methods.

Findings

SPT-like surveys can constrain hot gas in halos >10^{13} h^{-1}Msun.

Cross-correlation with galaxy luminosity can probe gas in halos down to 10^{13} h^{-1}Msun.

Upcoming surveys will enable studies of hot gas in low-mass halos.

Abstract

We investigate the potential of exploiting the Sunyaev-Zeldovich effect (SZE) to study the properties of hot gas in galaxy groups. It is shown that, with upcoming SZE surveys, one can stack SZE maps around galaxy groups of similar halo masses selected from large galaxy redshift surveys to study the hot gas in halos represented by galaxy groups. We use various models for the hot halo gas to study how the expected SZE signals are affected by gas fraction, equation of state, halo concentration, and cosmology. Comparing the model predictions with the sensitivities expected from the SPT, ACT and Planck surveys shows that a SPT-like survey can provide stringent constraints on the hot gas properties for halos with masses M ~> 10^{13} h^{-1}Msun. We also explore the idea of using the cross correlation between hot gas and galaxies of different luminosity to probe the hot gas in dark matter halos without identifying galaxy groups to represent dark halos. Our results show that, with a galaxy survey as large as the Sloan Digital Sky Survey and with the help of the conditional luminosity function (CLF) model, one can obtain stringent constraints on the hot gas properties in halos with masses down to 10^{13} h^{-1}Msun. Thus, the upcoming SZE surveys should provide a very promising avenue to probe the hot gas in relatively low-mass halos where the majority of L*-galaxies reside.