6 HZ QUASI-PERIODIC OSCILLATIONS FROM LOW-MASS X-RAY BINARIES - THE SOUND OF AN ACCRETION DISK

1992-04-01
ALPAR, MA
HASINGER, G
SHAHAM, J
YANCOPOULOS, S
Quasiperiodic oscillations (QPOs) at frequencies of 5-8 Hz are a common feature of low-mass X-ray binaries (LMXBs) during their normal branch (NB) spectral states. We propose that this frequency band is essentially a band of rotation frequencies in a thick accretion disk. The high luminosities in the NB state give rise to the thick disk and slow down the dynamical timescales. Density and optical-thickness perturbations in a subsonic region of the disk have the frequency spectrum of sound in a rotating medium. X-rays scattered through the subsonic region are modulated by long wavelength optical-thickness oscillations whose frequencies, determined by the rotation rate and vorticity, are observed as the NB QPOs.

Citation Formats
M. ALPAR, G. HASINGER, J. SHAHAM, and S. YANCOPOULOS, “6 HZ QUASI-PERIODIC OSCILLATIONS FROM LOW-MASS X-RAY BINARIES - THE SOUND OF AN ACCRETION DISK,” ASTRONOMY & ASTROPHYSICS, vol. 257, no. 2, pp. 627–631, 1992, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/67411.