Presentation #117.07 in the session Time-Domain Astrophysics.
The identification of compact object type as either black hole (BH) or neutron star (NS) is fundamental to understanding their formation and evolution. To date, time-domain determination of compact object type, which has been enormously successful in studies of individual Galactic and extragalactic sources, remains a relatively untapped tool in population studies. Measurement of orbital periods, pulsations, and bursts will lead to a revolution in the study of the demographics of NS and BH populations, linking source phenomena to accretion and galaxy parameters (e.g., star formation, metallicity). Here we summarize how the capabilities of the Athena WFI instrument (large collecting area, large field of view, good angular resolution and excellent timing resolution) make it an ideal instrument for this work.