A unified model of accretion flows and X ray emission in low mass X ray binary systemsRecent work on a unified model of accretion flows and X-ray emission in low mass X-ray binaries is summarized. In this model, a weakly magnetic neutron star accretes gas simultaneously from a Keplerian disk and a corona above the inner part of the disk. Photons are produced and escape through an approximately radial inflow of gas captured from the inner disk corona. Changes in the optical depths of the central corona and the radial flow may explain the Z-shaped hardness-intensity and color-color tracks observed in the most luminous sources. Numerical simulations show that the radial flow oscillates when the luminosity rises to within a few percent of the Eddington critical luminosity L sub E, and that the oscillation frequency is approximately 5 to 10 Hz if the radial flow develops approximately 300 km from the neutron star. The 10 to 20 Hz oscillations observed in Sco X-1 when it is on the flaring branch are discussed.
Document ID
19900016426
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Lamb, F. K. (Illinois Univ. Urbana-Champaign, IL, United States)
Date Acquired
September 6, 2013
Publication Date
November 1, 1989
Publication Information
Publication: ESA, The 23rd ESLAB Symposium on Two Topics in X Ray Astronomy. Volume 1: X Ray Binaries