Accretion-to-jet energy conversion efficiency in GW170817

Understand

Based on previously published multi-wavelength modelling of the GRB 170817A jet afterglow, that includes information from the VLBI centroid motion, we construct the posterior probability density distribution on the total energy in the bipolar jets launched by the GW170817 merger remnant.

• By applying a new numerical-relativity-informed fitting formula for the accretion disk mass, we construct the posterior probability density distribution of the GW170817 remnant disk mass.
• By combining the two, we estimate the accretion-to-jet energy conversion efficiency in this system, carefully accounting for uncertainties.
• The accretion-to-jet energy conversion efficiency in GW170817 is $\eta\sim 10^{-3}$ with an uncertainty of slightly less than two orders of magnitude.