Indirect imaging of the accretion stream in eclipsing polars – III. HU Aquarii low state.

We apply our technique for indirect imaging of the accretion stream to the polar HU Aqr, using eclipse profiles observed when the system was in a low-accretion state. The eclipse profile is different from that in the high state, and more variable from cycle to cycle. We find that the stream maps are brightest near the white dwarf and there is no significant brightening in the threading region. In the low state the stream threads on to the magnetic field closer to the L[sub 1] point than in the high state, with a footpoint of the accreting field line at high latitude. We then produce maps of the accretion region from polarimetry using Stokes imaging. These show that the majority of the accretion occurs near the equator. The difference between the maps may be explained if most of the stream material is not emitting significantly in the low state. If so, neither the stream eclipse mapping nor Doppler tomography techniques will trace the bulk of the accretion flow between the two stars. [ABSTRACT FROM AUTHOR]