M83 X-ray binary classifications from HST

Rather than classifying low-versus high-mass XRBs based on the scaling of the number of X-ray sources with stellar mass and star formation rate, respectively, we utilize multiband Hubble Space Telescope imaging data to classify each Chandra-detected compact X-ray source as a low-mass (i.e., donor mass <~3M_{sun}_), high-mass (donor mass >~8M_{sun}_), or intermediate-mass XRB based on either the location of its candidate counterpart on optical color-magnitude diagrams or the age of its host star cluster.

In addition to the standard (single and/or truncated) power-law functional shape, we approximate the resulting XLFs with a Schechter function. We identify a marginally significant (at the 1{sigma}-to-2{sigma} level) exponential downturn for the high-mass XRB XLF, at l~38.48_-0.33_^+0.52^ (in log CGS units). In contrast, the low- and intermediate-mass XRB XLFs, as well as the total XLF of M83, are formally consistent with sampling statistics from a single power law.