Comparing The High Mass X-ray Binary Populations of M31 and M33

M31 and M33 are ideal environments in which to study extragalactic high mass X-ray binaries (HMXBs) due to their proximity. We can resolve these galaxies’ stellar populations and use these observations to study their HMXB populations in detail and in the context of their parent stellar populations. While at a similar distance, M31 and M33 have different star formation rate intensities and metallicities, allowing us to probe the impact that these galaxy-wide properties have on their HMXB populations. We use overlapping deep Chandra and Hubble Space Telescope surveys in M31 and M33 to identify HMXB candidates, characterize their donor stars using spectral-energy distribution fitting, and measure the HMXB age distribution and production rate using spatially resolved star formation history maps. I will present the population demographics of the candidate HMXB populations of M31 and M33 and discuss what we can learn about massive binary stellar evolution by comparing the two populations.