Neutral versus ionized absorber as an explanation of the X-ray dippers
We present results of the Suzaku observation of the dipping, periodically bursting low mass X-ray binary XB 1323-619 in which we concentrate of the spectral evolution in dipping in the energy range 0.8 - 70 keV. It is shown that spectral evolution in dipping is well-described by absorption on the bulge in the outer accretion disk of two continuum components: emission of the neutron star plus the dominant, extended Comptonized emission of the accretion disk corona (ADC). This model is further supported by detection of a relatively small, energy-independent decrease of flux above 20 keV due to Thomson scattering. It is shown that this is consistent with the electron scattering expected of the bulge plasma. We address the recent proposal that the dip sources may be explained by an ionized absorber model giving a number of physical arguments against this model. In particular, that model is inconsistent with the extended nature of the ADC for which the evidence is now overwhelming.