Astronomy Colloquium

I will present recent numerical simulations of the dynamics and observational signatures of gas flows from gravitational wave sources. I will show that cosmological short GRBs share the same outflow structure with binary neutron star merger GW170817 in the afterglow stage: an ultra-relativistic structured jet, and that the exceptional properties of the GW170817 afterglow can be explained by the difference in observation angle alone. I will then show that the light curves of the GW170817 afterglow, if viewed on-axis, are consistent with those of cosmological short GRBs. As time allows, I will also discuss recent results from simulations of binary black hole accretion.