SIMBAD references

Observations of HZ Her/Her X-1 by the Rossi X-ray Timing Explorer during High State X-ray eclipses are analyzed. After a sharp ingress caused by the neutron star receding behind the companion star HZ Her, X-ray flux smoothly declines to a minimum at mid-eclipse. It then increases smoothly until egress. The mid-eclipse flux implies an extended emission region around the neutron star that is larger than that of HZ Her. The constancy of the X-ray softness ratio is consistent with electron scattering by an ionized corona. The corona is modeled as spherically symmetric with a power-law density profile. We find a best fit of ∝r^–1.25 with a normalization of ≃ 10¹²/cm3 at r = 2x10¹⁰ cm. The corona could either be in hydrostatic equilibrium, with heating by Compton scattering, a fast outflow, with a high mass-loss rate of ∼10¹⁸ gm/s, or a hybrid, with an inner hydrostatic region and outer slow flow with a low mass-loss rate. A brightening at orbital phase 0.94 is suggested to be caused by the impact of the accretion stream with the accretion disk.