Measuring interacting binary mass functions with X-ray fluorescence

ABSTRACT The masses of compact objects in X-ray binaries are best constrained through dynamical measurements, relying on radial velocity curves the companion star. In anticipation upcoming high spectral resolution telescopes, we explore their potential to constrain mass function object. Fe K line fluorescence is a common feature spectra luminous binaries, with Doppler-broadened component from inner accretion disc extensively studied. If corresponding narrow irradiated can be isolated, this provides an opportunity further binary system properties. Here, model geometry determine star’s solid angle, and deduce iron line’s equivalent width. We find that for systems ratio q > 0.1, expected K? width 2–40 eV. Simulations using xspec indicate new microcalorimeters will have sufficient able produce emission-line measurements precision 5–40 km s?1, source continuum fluxes exceeding 10?12 erg cm?2 s?1. Several caveats need considered; method dependent successful isolation broad component, observation clear changes independent scatter arising complex wind behaviour. These issues remain proven microcalorimeters, but has parameters where optical not viable.