## Inferring prompt black-hole formation in neutron star mergers from gravitational-wave data

In 1908.05442 we present two methods to infer the probability of prompt black hole formation in neutron star merger by analyzing the inspiral gravitational-wave signal solely. Both methods combine the posterior distribution from the gravitational-wave data analysis with numerical relativity results. One method relies on the use of phenomenological models for the equation of state and on the estimate of the collapse threshold mass. The other is based on the estimate of the tidal polarizability parameter that is correlated in an equation-of-state agnostic way with the prompt BH formation. Our approach helps interpreting events for which the LIGO-Virgo sensitivity at high frequencies is not sufficient to detect the signal corresponding to the merger and post-merger phases, like GW170817. By applying the methods to GW170817 data we find that they consistently predict a probability of ~ 50-70% for prompt black-hole formation, which however significantly decreases below 10% if the maximum mass constraint from PSR J0348+0432 or PSR J0740+6620 is imposed.

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