Normal Galaxy Studies with Next-generation X-ray surveys: eROSITA and Athena WFI

Upcoming future X-ray surveys like eROSITA and Athena WFI will detect 10-100 times more normal (i.e., non-AGN) galaxies than previous X-ray surveys, and therefore, vastly enhance our understanding of X-ray emission from X-ray binaries and hot gas within galaxies. For example, multiple scans of particular objects may reveal transient sources. Additionally, such complete and unbiased surveys of galaxies may lead to discoveries of rare and unique X-ray sources within galaxies. We can also use these wide field surveys to measure and quantify scatter in X-ray scaling relations with physical galaxy properties (e.g., stellar mass, star formation rates, metallicities and star formation histories). Using existing multiwavelength surveys, we predict what we expect to observe in these wide-field X-ray surveys. We present the status of current X-ray surveys and put next-generation X-ray surveys into context in terms of key parameters such as X-ray flux and solid angle surveyed.