Ginga Studies of Black Hole Candidates: Multiwavelength Studies Using TemporalLags and Coherence Function Analysis and Ginga Archival Studies of QPOs in LMXB Z-Sources

摘要

We present a modified beat frequency modulated accretion model appropriate to adescription of the horizontal branch oscillations of Z-type low-mass x-ray binaries. This model incorporates several new physical elements: (i) magnetic screening by the accretion disk and neutron star, (ii) radiation pressure dominance in the inner disk, and (iii) stellar rotation effects. Fitted to observational data, the model constrains the surface magnetic field in a typical LMXlB Z source to be less than 1O deg G and the stellar spin frequency to be greater than 400 Hz. The predicted high stellar spin frequency falls in a range where observational upper limits on pulsation are not a constraint. The derived magnetic field and spin frequency range are compatible with the fastest radio pulsars.