Ultra wide black-hole - neutron star binaries as a possible source for gravitational waves and short gamma ray bursts

Understand

The third observing run of the LIGO/Virgo/KARGA collaboration reported a few neutron star - black hole (NSBH) merger events.

• While NSBH mergers have yet to receive extensive theoretical attention, they may have a promising electromagnetic signature in the form of short gamma - ray bursts.
• Here we show that NSBH dynamical mergers can naturally form from ultra - wide binaries in the field.
• Flyby gravitational interactions with other neighbors in the galaxy in these ultra - wide systems may result in high eccentricity that drives the binary into a merger.