Rotational disturbance in the intermediate polar BG Canis Minoris

I report on the independent discovery of a feature in the intermediate polar BG Canis Minoris which resembles a rotational disturbance. A similar effect has already been reported by de Martino et al., but in the HeII lambda 4686 line only, whereas the data presented here show the effect in the Balmer lines only. Another difference is that the new disturbance occurs at phase 0.75 - this is 0.25 orbital cycles prior to that reported previously. There is, however, indication of a change in the V/R ratio at phase zero as well, in phase with that reported previously, and in phase with an apparent eclipse of the HeII lambda 4686 line flux. These results corroborate the suggestion of de Martino et al. that BG CMi is at a relatively high inclination, and moreover imply that some intriguing and previously unseen transient behaviour is at work in this system.