Item

Abstract

The Equation of State (EOS) of dense strongly-interacting matter can be
probed by astrophysical observations of neutron stars (NS), such as X-ray
detections of pulsars or the measurement of the tidal deformability of NSs
during the inspiral stage of NS mergers. These observations constrain the EOS
at most up to the density of the maximum-mass configuration, $n_\textrm{TOV}$,
which is the highest density that can be explored by stable NSs for a given
EOS. However, under the right circumstances, binary neutron star (BNS) mergers
can create a postmerger remnant that explores densities above $n_\textrm{TOV}$.
In this work, we explore whether the EOS above $n_\textrm{TOV}$ can be measured
from gravitational-wave or electromagnetic observations of the postmerger
remnant. We perform a total of twenty-five numerical-relativity simulations of
BNS mergers for a range of EOSs and find no case in which different
descriptions of the matter above $n_{\rm TOV}$ have a detectable impact on
postmerger observables. Hence, we conclude that the EOS above $n_\textrm{TOV}$
can likely not be probed through BNS merger observations for the current and
next generation of detectors.