Numerical-relativity simulations of long-lived remnants of binary neutron star mergers. (arXiv:1910.04036v1 [gr-qc])
<a href="http://arxiv.org/find/gr-qc/1/au:+Pietri_R/0/1/0/all/0/1">Roberto De Pietri</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Feo_A/0/1/0/all/0/1">Alessandra Feo</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Font_J/0/1/0/all/0/1">José A. Font</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Loffler_F/0/1/0/all/0/1">Frank Löffler</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Pasquali_M/0/1/0/all/0/1">Michele Pasquali</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Stergioulas_N/0/1/0/all/0/1">Nikolaos Stergioulas</a>
We analyze the properties of the gravitational wave signal emitted after the
merger of a binary neutron star system when the remnant survives for more than
a 80 ms (and up to 140ms). We employ four different piecewise polytropic
equations of state supplemented by an ideal fluid thermal component. We find
that the post-merger phase can be subdivided into three phases: an early
post-merger phase (where the quadrupole mode and a few subdominant features are
active), the intermediate post-merger phase (where only the quadrupole mode is
active) and the late post-merger phase (where convective instabilities trigger
inertial modes). The inertial modes have frequencies somewhat smaller than the
quadrupole modes. In one model, we find an interesting association of a
corotation of the quadrupole mode in parts of the star with a revival of its
amplitude. The gravitational wave emission of inertial modes in the late
post-merger phase is concentrated in a narrow frequency region and is
potentially detectable by the planned third-generation detectors. This allows
for the possibility of probing not only the cold part of the equation of state,
but also its dependence on finite temperature. In view of these results, it
will be important to investigate the impact of various type of viscosities on
the potential excitation of inertial modes in binary neutron star merger
remnants.
We analyze the properties of the gravitational wave signal emitted after the
merger of a binary neutron star system when the remnant survives for more than
a 80 ms (and up to 140ms). We employ four different piecewise polytropic
equations of state supplemented by an ideal fluid thermal component. We find
that the post-merger phase can be subdivided into three phases: an early
post-merger phase (where the quadrupole mode and a few subdominant features are
active), the intermediate post-merger phase (where only the quadrupole mode is
active) and the late post-merger phase (where convective instabilities trigger
inertial modes). The inertial modes have frequencies somewhat smaller than the
quadrupole modes. In one model, we find an interesting association of a
corotation of the quadrupole mode in parts of the star with a revival of its
amplitude. The gravitational wave emission of inertial modes in the late
post-merger phase is concentrated in a narrow frequency region and is
potentially detectable by the planned third-generation detectors. This allows
for the possibility of probing not only the cold part of the equation of state,
but also its dependence on finite temperature. In view of these results, it
will be important to investigate the impact of various type of viscosities on
the potential excitation of inertial modes in binary neutron star merger
remnants.
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