A Parametrized Equation of State for Neutron Star Matter with Continuous Sound Speed

We present a generalized piecewise polytropic parameterization for the neutron-star equation of state using an ansatz that imposes continuity in not only pressure and energy density, but also in the speed of sound. The universe of candidate equations of state is shown to admit preferred dividing den...

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Bibliographic Details
Published inarXiv.org
Main Authors O'Boyle, Michael F, Markakis, Charalampos, Stergioulas, Nikolaos, Read, Jocelyn S
Format Paper Journal Article
LanguageEnglish
Published Ithaca Cornell University Library, arXiv.org 05.10.2020
Subjects
Computer simulation
Equations of state
Flux density
Formability
Neutron stars
Neutrons
Numerical relativity
Parameter estimation
Parameterization
Physics - General Relativity and Quantum Cosmology
Physics - High Energy Astrophysical Phenomena
Relativity
Waveforms
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Summary:We present a generalized piecewise polytropic parameterization for the neutron-star equation of state using an ansatz that imposes continuity in not only pressure and energy density, but also in the speed of sound. The universe of candidate equations of state is shown to admit preferred dividing densities, determined by minimizing an error norm consisting of integral astrophysical observables. Generalized piecewise polytropes accurately reproduce astrophysical observables, such as mass, radius, tidal deformability and mode frequencies, as well as thermodynamic quantities, such as the adiabatic index. This makes the new EOS useful for Bayesian parameter estimation from gravitational waveforms. Moreover, since they are differentiable, generalized piecewise polytropes can improve pointwise convergence in numerical relativity simulations of neutron stars. Existing implementations of piecewise polytropes can easily accommodate this generalization.
ISSN:2331-8422
DOI:10.48550/arxiv.2008.03342