1995A&A...303..801K

We report the detection of 26Hz quasi-periodic oscillations during an 800s intensity dip in the low-mass X-ray binary CygX-2 in the flaring branch state. The quasi-periodic oscillations have properties that are different from those of flaring branch quasi-periodic oscillations seen in other "Z" sources, which are often ascribed to oscillations in a radial inflow of matter. The fact that the 26Hz quasi-periodic oscillations occur during a dip suggests that they arise in a medium that partially obscures the X-ray emission. We interpret the new quasi-periodic oscillations phenomenon in terms of a model involving a radial flow and a thick, torus-like inner disk.