Thermal Sunyaev-Zel'dovich and Diffuse X-Ray Emission Cross Correlation

The gas within dark matter halos of galaxies and clusters contains information about the baryon content of the universe that is not found anywhere else. Precise understanding of the nuances of this gas is critical to understanding the fundamental laws of the universe. There is a constant feedback loop between theoretical modeling of that gas and observations searching for its structures. Since this gas is not directly detectable, we must search the universe for traces of how it affects its surroundings. One such probe is how the gas alters the temperature of the Cosmic Microwave Background (CMB) when the photons of the Big Bang scatter off of the electrons in that gas through the Thermal Sunyaev-Zel’dovich (tSZ) effect. This inverse Compton scattering of the photons creates a measurable decriment of the temperature spectrum of the CMB in the 0.5-2 keV energy band. In addition, there is another powerful probe of halo gas in this energy band: X-ray emission. This emission comes in two forms: the first is X-ray emission from the gas itself due to its temperature, the second is the Active Galactic Nuclei (AGN) X-ray emission from the supermassive black holes at the center of clusters. With these two types of X-ray emission, we can make two independent estimates for the baryon content of these clusters. We can combine these probes of the gas content of these halos statistically using power spectral analysis. From these power spectra, we can compare various models of the gas with actual data. In this thesis, we explore the feedback loop in the study of halo gases by looking at current experiments in the field for detections of halo gas and modeling current and future missions to make predictions on what detectors will see in the near future.