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Free keywords:
General Relativity and Quantum Cosmology, gr-qc, Astrophysics, High Energy Astrophysical Phenomena, astro-ph.HE, Astrophysics, Solar and Stellar Astrophysics, astro-ph.SR
Abstract:
Determining the equation of state of matter at nuclear density and hence the
structure of neutron stars has been a riddle for decades. We show how the
imminent detection of gravitational waves from merging neutron star binaries
can be used to solve this riddle. Using a large number of accurate
numerical-relativity simulations of binaries with nuclear equations of state,
we find that the postmerger emission is characterized by two distinct and
robust spectral features. While the high-frequency peak has already been
associated with the oscillations of the hypermassive neutron star produced by
the merger and depends on the equation of state, a new correlation emerges
between the low-frequency peak, related to the merger process, and the total
compactness of the stars in the binary. More importantly, such a correlation is
essentially universal, thus providing a powerful tool to set tight constraints
on the equation of state. If the mass of the binary is known from the inspiral
signal, the combined use of the two frequency peaks sets four simultaneous
constraints to be satisfied. Ideally, even a single detection would be
sufficient to select one equation of state over the others. We test our
approach with simulated data and verify it works well for all the equations of
state considered.
