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Three-dimensional Doppler tomography has been used to study the Hα emission sources in the RS Vulpeculae interacting binary. The 2D tomogram of this binary suggested that most of the emission arose from the cool mass losing star with additional evidence of gas flowing close to the predicted trajectory. However, the 3D tomogram revealed surprising evidence of a more pronounced gas stream flow at high V z velocities from -240 to -360 km s −1 . This behavior is most likely caused by magnetic activity on the cool star since the central velocity plane, defined by V z = 0 km s −1 , should be coincident with the orbital plane of the binary if the flow is dominated by gravitational forces only. RS Vul has been detected as both an X-ray and a radio source, and it is possible that the RS Vul gas stream may have been deflected by magnetic field lines. This flow is distinctly different from that found in the streamlike state of U CrB, in which the gas flow was confined mostly to the central velocity plane.

The 3D Radioastronomical Approach to Doppler tomography has been used to study the Hα emission sources in U Coronae Borealis. These 3D tomograms provide greater resolution than the projected 2D version and highlight the jet-like gas flows in the V z direction transverse to the orbital plane. In this paper, the 3D tomograms are compared at two distinct epochs when U CrB was in the disk-like state (1993 data) and the stream-like state (1994 data). Both states display a prominent emission source, the circumprimary bulge, which is produced when the gas stream strikes the photosphere of the mass-gainer. This source is detected within V z = ±150 km s −1 , and demonstrates that the bulge is not confined to the orbital plane although it achieves maximum strength near V z =0 km s −1 . Other emission sources include the stream-star and stream-disk shocks and a Localized Region (LR) where the circling disk material strikes the incoming gas stream. The LR has V z velocities of 200 to 500 km s −1 in the disk-like state. The disk emission is seen over a range of V z velocities, and there is evidence that the disk is inclined to the orbital plane or may have two arms. The gas stream flows along its predicted trajectory in the stream-like state, and a comparison with the disk-like state suggests that the gas stream has a higher density than the disk in both states of this binary.

Abstract. VLT FORS 1 observations indicate the presence of a variable significant magnetic field in the X-ray binary Cyg X-1. The importance of this investigation comes from the fact that it rules one of the most significant BH manifestations: the X-ray millisecond flickering, usually related to reconnection of magnetic lines in the innermost part of the accretion disc.

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