Jet-driven and jet-less fireballs from compact binary mergers

Understand

During a compact binary merger involving at least one neutron star, a small fraction of the gravitational energy could be liberated in such a way to accelerate a small fraction (~ 10^-6) of the neutron star mass in an isotropic or quasi-isotropic way.

• In presence of certain conditions, a pair-loaded fireball can form, which undergoes accelerated expansion reaching relativistic velocities.
• As in the standard fireball scenario, internal energy is partly transformed into kinetic energy.
• At the photospheric radius, the internal radiation can escape, giving rise to a pulse that lasts for a time equal to the delay time since the merger.