GINGA AND ROSAT OBSERVATIONS OF AO PSC AND V1223 SGR

We present results from X-ray observations of the intermediate polars AO Pac and V1223 Sgr, taken with the ROSAT HRI and the Ginga LAG. Both sources show sinusoidal modulation at the white dwarf spin period in all energy bands, possibly with the exception of the highest. The dept hs of these modulations increase at lower energy, but the rates at whi ch they do so are not consistent with single column densities of absor bing material. Neither source shows any significant pulse at the beat period, which argues for a predominantly disc-fed accretion model in e ach case. The AO Psc observations show a modulation at the orbital per iod, which in the ROSAT data may indicate an extended absorbing struct ure, with a dip at orbital phase similar to 0.5-0.8 superimposed. The V1223 Sgr ROSAT data show short dips which occur intermittently at aro und orbital phase 0.8. These dips vary in duration and phase of commen cement and suggest that the system inclination angle is just sufficien t for our line of sight to graze the upper extent of the material thro wn out of the disc plane.