Neutron stars in quasi-topological gravity can be more compact than black holes and radially stable across several equations of state.
Analytical representations of unified equations of state for neutron-star matter
9 Pith papers cite this work. Polarity classification is still indexing.
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Pith papers citing it
abstract
Context. A unified equation of state (EoS) should describe the crust and the core of a neutron star using the same physical model. The Brussels-Montreal group has recently derived a family of such EoSs based on the nuclear energy-density functional theory with generalized Skyrme effective forces, fitted to the available mass data. At the same time, these forces were constrained to reproduce microscopic calculations of homogeneous neutron matter based on realistic two- and three-nucleon forces. Aims. We represent basic physical characteristics of the latest Brussels-Montreal EoS models by analytical expressions to facilitate their inclusion in astrophysical simulations. Methods. We consider three EoS models, which significantly differ by stiffness: BSk19, BSk20, and BSk21. For each of them we constructed two versions of the EoS parametrization. In the first version, pressure P and gravitational mass density \rho are given as functions of the baryon number density n_b. In the second version, P, \rho, and n_b are given as functions of pseudo-enthalpy, which is useful for two-dimensional calculations of stationary rotating configurations of neutron stars. In addition to the EoS, we derived analytical expressions for several related quantities that are required in neutron-star simulations: number fractions of electrons and muons in the stellar core, nucleon numbers per nucleus in the inner crust, and equivalent radii and shape parameters of the nuclei in the inner crust. Results. We obtain analytical representations for the basic characteristics of the models of cold dense matter, which are most important for studies of neutron stars. We demonstrate the usability of our results by applying them to calculations of neutron-star mass-radius relations, maximum and minimum masses, thresholds of direct Urca processes, and the electron conductivity in the neutron-star crust.
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representative citing papers
Bayesian NS EoS study using full nuclear posterior distributions and consistent crust modeling finds increased surface thickness and crustal moment of inertia relative to prior work.
Increasing the bosonic dark matter fraction in admixed neutron stars shifts axial quasi-normal mode frequencies and damping times, can reorder mode hierarchy, and drives a transition from neutron-star-like to boson-star-like ringdown behavior.
Large initial baryon asymmetry allows Hubble patches to collapse into primordial neutron stars arrested by nuclear pressure, requiring later entropy dilution to match observed Y_B and BBN.
Dark matter admixed neutron stars show up to 12% thinner crusts and higher torsional oscillation frequencies than pure neutron stars when dark matter forms a core, with analytical formulas matching numerics at sub-percent level.
In scalar-vector-tensor gravity, the vector-curvature coupling alters neutron star mass-radius curves and radial oscillation frequencies while preserving the coincidence of maximum mass with the onset of radial instability.
A gauged U(1)_{Lμ-Lτ} model generates nearly degenerate Majorana dark matter whose self-interactions via a light scalar mediator set the relic density, resolve core-cusp anomalies, and fit LZ direct detection plus muon g-2 bounds.
Neutron stars with primary scalar hair in a DHOST subfamily are more compact than GR predictions and develop singularities above a critical scalar charge threshold.
Axial w-mode frequencies of anisotropic neutron stars decrease monotonically with mass, depend approximately linearly on compactness with anisotropy modifying slope and intercept, damping times increase with mass, and empirical expressions are given for both as functions of compactness and anisotrop
citing papers explorer
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Neutron stars more compact than black holes in quasi-topological gravity: Equilibrium configurations and radial stability
Neutron stars in quasi-topological gravity can be more compact than black holes and radially stable across several equations of state.
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Properties of the neutron star crust informed by nuclear structure data
Bayesian NS EoS study using full nuclear posterior distributions and consistent crust modeling finds increased surface thickness and crustal moment of inertia relative to prior work.
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Axial Quasi-normal Modes of Admixed Neutron Stars
Increasing the bosonic dark matter fraction in admixed neutron stars shifts axial quasi-normal mode frequencies and damping times, can reorder mode hierarchy, and drives a transition from neutron-star-like to boson-star-like ringdown behavior.
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Primordial Neutron Stars
Large initial baryon asymmetry allows Hubble patches to collapse into primordial neutron stars arrested by nuclear pressure, requiring later entropy dilution to match observed Y_B and BBN.
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The crust of dark-matter admixed neutron stars: bulk properties and torsional oscillations
Dark matter admixed neutron stars show up to 12% thinner crusts and higher torsional oscillation frequencies than pure neutron stars when dark matter forms a core, with analytical formulas matching numerics at sub-percent level.
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Radial Oscillations of Neutron Stars with Vector-Induced Scalar Hair
In scalar-vector-tensor gravity, the vector-curvature coupling alters neutron star mass-radius curves and radial oscillation frequencies while preserving the coincidence of maximum mass with the onset of radial instability.
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Nearly Degenerate Majorana Dark Matter and Its Self-Interactions in a Gauged $U(1)_{L_\mu - L_\tau}$ Model
A gauged U(1)_{Lμ-Lτ} model generates nearly degenerate Majorana dark matter whose self-interactions via a light scalar mediator set the relic density, resolve core-cusp anomalies, and fit LZ direct detection plus muon g-2 bounds.
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Neutron stars with primary scalar hair
Neutron stars with primary scalar hair in a DHOST subfamily are more compact than GR predictions and develop singularities above a critical scalar charge threshold.
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Axial $w$-modes of anisotropic neutron stars
Axial w-mode frequencies of anisotropic neutron stars decrease monotonically with mass, depend approximately linearly on compactness with anisotropy modifying slope and intercept, damping times increase with mass, and empirical expressions are given for both as functions of compactness and anisotrop