Quasi-periodic Oscillations in the X-Ray Flux of the Rapid Burster (MXB 1730-335)
Haberl, F.; Stella, L.; Parmar, A. N.; White, N. E.; van Paradijs, J.; Lewin, W. H. G.
Netherlands, United States
Abstract
The authors report on the results of an EXOSAT observation of the "Rapid Burster" in 1985 August during an active state. Forty 1 - 10 minute long type 2 bursts were detected together with persistent emission. Quasi-periodic oscillations (QPO) were observed in 23 bursts with frequencies between 2 and 5 Hz. The average frequency of the QPO during the bursts was anticorrelated with the average burst flux, and the rms strength of the QPO was as high as ≡20% during the longest bursts. Among the models for QPO in low-mass X-ray binaries that involve the presence of a neutron star magnetosphere, only the beat frequency model is still consistent with the QPO properties of the Rapid Burster.