Multimessenger signals from black hole-neutron star mergers without significant tidal disruption

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We study the multimessenger signals from the merger of a black hole with a magnetized neutron star using resistive magnetohydrodynamics simulations coupled to full general relativity.

• We focus on a case with a 5:1 mass ratio, where only a small amount of the neutron star matter remains post-merger, but we nevertheless find that significant electromagnetic radiation can be powered by the interaction of the neutron star's magnetosphere with the black hole.
• In the lead-up to merger, strong twisting of magnetic field lines from the inspiral leads to plasmoid emission and results in a luminosity in excess of that expected from unipolar induction.
• We find that the strongest emission occurs shortly after merger during a transitory period in which magnetic loops form and escape the central region.