Speaker
Description
X-ray eclipse mapping is a valuable modelling technique capable of constraining the mass and radius of compact objects in eclipsing binaries and probing the outflow from the companion star. In this talk, I will demonstrate the capabilities and recent developments of the X-ray Transit and EClipse software, X-TREC, through the modelling of the X-ray eclipses observed in three systems: the neutron star (NS) low mass X-ray binaries (LMXBs) EXO 0748--676 and Swift J1858.6--0814 and the black hole (BH) high mass X-ray binary (HMXB) M33 X-7. In all cases, we obtain tight constraints on the mass ratio and binary inclination. These measurements, when combined with radial velocity amplitudes from stellar absorption/emission lines, can place constraints on the masses of the binary components. For example, we combine our measured binary mass ratio, q ~ 0.2, and inclination, ~ 76.5 degrees, from mapping the XMM-Newton eclipses of EXO 0748--676, with the previously measured radial velocity of 410 km/s, derived from Doppler mapping analysis of H-alpha emission during quiescence by Bassa et al. (2009). This returns an NS mass of ~ 2 solar masses, thus favouring a hard equation of state. We further uncover evidence for irradiation-driven ablation in Swift J1858.6--0814 and EXO 0748--676, revealing their relation to spider pulsars.
