Can we measure the collapse time of a post-merger remnant for a future GW170817-like event?

Measuring the collapse time of a binary neutron star merger remnant can inform the physics of extreme matter and improve modelling of short gamma-ray bursts and associated kilonova. The lifetime of the post-merger remnant directly impacts the mechanisms available for the jet launch of short gamma-ray bursts. We develop and test a method to measure the collapse time of post-merger remnants. We show that for a GW170817-like event at $sim!40,$Mpc, a network of Einstein Telescope with Cosmic Explorer is required to detect collapse times of $sim!10,$ms. For a two-detector network at A+ design sensitivity, post-merger remnants with collapse times of $sim!10,mathrm{ms}$ must be $lesssim 10,$Mpc to be measureable. This increases to $sim!18-26,$Mpc if we include the proposed Neutron star Extreme Matter Observatory (NEMO), increasing the effective volume by a factor of $sim!30$.