On the putative class of B[e] X-ray binaries

Abstract

We discuss the putative class of B[e] X-ray binaries, with reference to currently identified candidate systems, focusing on CI Cam and the newly identified class of highly obscured hard X-ray sources detected by INTEGRAL. We suggest that such a class will likely consist of two types of object in which the B[e] phenomenon is (i) intrinsic to the mass donor or (ii) a result of binarity. Finally, we discuss the difficulties inherent in observing B[e] X-ray binaries and the physical motivations for their study, which include the origin of the Galactic hard X-ray emission and the propagation of jets in dense media