Salvesen Abstract: Spin-Orbit Misalignments in Microquasars

A microquasar consists of an evolved star in a binary orbit with a rotating black hole, thought to power outflowing jets to near-light speed. Conventional theory predicts these jets propagate along the black hole's spin axis, which need not be aligned to the binary orbital axis. The origin of these “spin-orbit misalignments” has implications for the formation pathways of coalescing black holes and measurements of black hole spin magnitudes. I will show that the standard pathway for binary evolution, followed by a supernova "kick" imparted to a newborn black hole, cannot explain the extreme spin-orbit misalignment in the microquasar V4641 Sgr. This result has two interpretations: (1) V4641 Sgr did not form through the traditional binary evolution pathway, as it is currently understood; and/or (2) the jet does not reliably trace the black hole's spin axis. Despite being a study of a single object, the possible implications to all black holes in binary systems are significant.