X-ray Binary Population Luminosity Functions in Galaxies and their Dependence on Star-Formation History and Metallicity

X-ray binary (XRB) populations in galaxies trace the demographics of close binaries, massive stars, and compact-object remnants; they provide important constraints on the accretion phase of close-binary evolution that connects to other astrophysically interesting sources (e.g., gamma-ray bursts and gravitational wave mergers); and their emission is expected to scale sensitively with the physical properties of their host galaxies (e.g., star-formation rate, stellar mass, metallicity, and stellar age). In this talk, we will present a new empirical framework modeling the metallicity and star-formation history (SFH) dependence of XRB population luminosity functions (XLFs) in normal galaxies. We test our model framework using ~2000 X-ray detected point-sources within 44 Chandra-observed galaxies at D ∼< 30 Mpc that span a broad range of metallicity and SFH (spanning early-to-late type morphologies). Our models provide unifying quantitative context for scaling relations that have been well studied in the literature, including, e.g., the high-mass XRB (HMXB) luminosity versus SFR relation (LX(HMXB)/SFR), the LX(HMXB)-SFR-metallicity plane, the ultraluminous X-ray source frequency as a function of metallicity and age, the low-mass XRB (LMXB) luminosity scaling with stellar mass (LX(LMXB)/M*), and the observed evolution of LX(HMXB)/SFR and LX(LMXB)/M* relations with cosmic time.