087090

We propose two NuSTAR observations of the M81 disk that together with existing observations of its bulge will provide complete coverage of its X-ray binary populations down to luminosities of 10elev38 erg-s. These observations together with a wealth of existing HST and multi-wavelength data will allow us to fully characterize its X-ray binary populations on the basis of their compact objects and donor stars. This will provide a complete picture of the demographics of the compact objects in a typical spiral galaxy and together with population synthesis models will allow us to constrain their formation and evolution paths.