  In light of the recent dazzling discovery of GW170817, we discuss several new
scientific opportunities that would emerge in multi-messenger time-domain
astrophysics if a facility like the next generation Very Large Array (ngVLA)
were to work in tandem with ground-based gravitational wave (GW) detectors.
These opportunities include probing wide-angle ejecta and off-axis afterglows
of neutron star (NS)-NS mergers; enabling direct size measurements of radio
ejecta from NS-NS mergers; and unraveling the physics behind the progenitors of
compact binary mergers via host galaxy studies at radio wavelengths. Our
results show that, thanks to its unprecedented sensitivity and resolution, the
ngVLA will enable transformational results in the multi-messenger exploration
of the transient radio sky.
