Microquasars are Galactic black hole systems in which matter is transferred from a donor star and accretes onto a black hole of, typically, 10-20 solar masses. The presence of an accretion disk and a relativistic jet made them a scaled down analogue of quasars-thence their name. Microquasars feature prominently in the scientific goals of X-ray polarimeters, because a number of open questions, which are discussed in this paper, can potentially be answered: the geometry of the hot corona believed to be responsible for the hard X-ray emission; the role of the jet; the spin of the black hole.
Matt, G., Tamborra, F.M. (2018). Studying microquasars with X-Ray polarimetry. GALAXIES, 6(1), 32 [10.3390/galaxies6010032].