Causality anchored to χEFT at low density implies the closed-form bound R(2.0 M_⊙) ≤ 1.16 R(1.4 M_⊙) − 1.1 km for neutron stars sharing one causal EoS, saturated by an analytic one-parameter family.
hub Mixed citations
A NICER View of the Nearest and Brightest Millisecond Pulsar: PSR J0437$\unicode{x2013}$4715
Mixed citation behavior. Most common role is background (67%).
abstract
We report Bayesian inference of the mass, radius and hot X-ray emitting region properties - using data from the Neutron Star Interior Composition ExploreR (NICER) - for the brightest rotation-powered millisecond X-ray pulsar PSR J0437$\unicode{x2013}$4715. Our modeling is conditional on informative tight priors on mass, distance and binary inclination obtained from radio pulsar timing using the Parkes Pulsar Timing Array (PPTA) (Reardon et al. 2024), and we use NICER background models to constrain the non-source background, cross-checking with data from XMM-Newton. We assume two distinct hot emitting regions, and various parameterized hot region geometries that are defined in terms of overlapping circles; while simplified, these capture many of the possibilities suggested by detailed modeling of return current heating. For the preferred model identified by our analysis we infer a mass of $M = 1.418 \pm 0.037$ M$_\odot$ (largely informed by the PPTA mass prior) and an equatorial radius of $R = 11.36^{+0.95}_{-0.63}$ km, each reported as the posterior credible interval bounded by the 16% and 84% quantiles. This radius favors softer dense matter equations of state and is highly consistent with constraints derived from gravitational wave measurements of neutron star binary mergers. The hot regions are inferred to be non-antipodal, and hence inconsistent with a pure centered dipole magnetic field.
hub tools
citation-role summary
citation-polarity summary
representative citing papers
Non-parametric EOS construction from crust to pQCD forces a sound-speed peak and softening that realizes a generalized quark-hadron crossover in massive neutron stars.
Strongly interacting dark matter described by a first-principles G2 gauge-theory equation of state can be mixed into neutron stars while remaining compatible with current observational constraints.
Slow hadron-quark conversion in hybrid neutron stars creates extended stable 'waterfall' branches, reviving stiff hadronic equations of state that rapid-conversion analyses reject.
Bayesian analysis of astrophysical and laboratory data favors the two-families scenario of coexisting hadronic and strange quark stars over the one-family scenario.
A physics-informed Bayesian neural network learns neutron-star equations of state from theoretical priors and constraints, then generates posterior mass-radius and mass-tidal-deformability distributions consistent with NICER radii and 2-solar-mass limits.
Emulator-assisted Bayesian inference of an extended Skyrme EDF, jointly constrained by nuclear observables, ab initio calculations, and NICER data, produces posteriors yielding consistent neutron star crust and core properties with a provided multivariate Gaussian for bulk nuclear matter parameters.
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.
RGOPT-resummed NNLO pQCD EoS for massive quarks in beta equilibrium is fitted and applied to construct pure quark stars (X=3.08-3.58) and hybrid stars (X~2-2.98) compatible with PSR J0740+6620 and GW190814.
Differential rotation in hybrid stars with deconfinement phase transition allows quasi-toroidal configurations with quark matter rings and leads to degeneracies in rotational profiles at mass-radius curve intersections.
Long-term numerical-relativity runs find isolated neutron stars with an external dipole relax to a stable mixed poloidal-toroidal field with toroidal energy ≲10% after Tayler saturation.
Bayesian analysis finds that the likely ranges of light dark-matter fermion mass and exponential density-profile parameter in hyperon-containing neutron stars are nearly independent of the hadronic model for symmetry-energy slopes between 40 and 58 MeV, with HESS J1731-347 and GW170817 data playing,
A Bayesian combination of eight M-R posteriors for PSR J0030+0451 yields M = 1.46^{+0.09}_{-0.08} M_⊙, R = 12.69^{+0.64}_{-0.55} km while marginalizing over unknown model systematics.
Hybrid neutron-star equations of state remain sensitive to the low-density nucleonic model at transition densities around 2ρ₀, with model spread in radius and tidal deformability exceeding observational uncertainty by factors of ~1.8 and ~1.4.
Vector-portal fermionic dark matter softens or stiffens the neutron-star equation of state depending on Z' mass, producing mass-radius and tidal-deformability signatures constrained by GW170817 and NICER.
Quasi-universal relations connect the trace anomaly profile of neutron star matter to stellar compactness, moment of inertia, and tidal deformability, yielding a central value estimate of Δ_c = 0.1770^{+0.0365}_{-0.0432} for a 1.4 M_⊙ star.
Dark matter cores heat baryonic matter in evolving proto-neutron stars by deepening the gravitational potential while halos cool it, providing a diagnostic distinct from hyperons.
The Lee-Huang-Yang beyond-mean-field correction measurably reduces the dimensionless moment of inertia of slowly rotating BEC dark stars at fixed compactness while preserving the I-Love universal relation to within a few percent.
Including hyperons reduces maximum neutron-star mass by 0.05-0.10 solar masses and increases radius at 1.4 solar masses by 0.5-0.8 km across all models while keeping every equation of state consistent with the 2-solar-mass limit.
Systematic scan of ΛNN and ΛΛN three-body force parameters in Skyrme EDF for beta-equilibrated hyperonic matter, TOV branch classification, and Bayesian analysis with XGBoost-SHAP on NS mass-radius constraints.
The quark-hadron mixed phase width in hybrid stars is mainly controlled by effective nucleon mass and symmetry energy, with temperature reducing the width and softening the EOS while strong vector repulsion is needed to match massive pulsar and NICER data.
A Poincaré-covariant vector-vector contact interaction yields an equation of state for strange quark matter whose mass-radius and tidal properties match pulsar and gravitational-wave constraints for two tuned parameter sets.
Nonparametric GP-based high-density extensions yield softer EOS posteriors with larger uncertainties than parametric PP extensions when jointly constrained by multi-messenger neutron star observations.
Comparative numerical study of radial modes in strange quark stars using CFL, interacting, and linear causal EOS shows all satisfy current mass-radius bounds and produce 4-7 kHz fundamental frequencies.
citing papers explorer
-
Causality alone bounds the maximum radius difference between different-mass neutron stars
Causality anchored to χEFT at low density implies the closed-form bound R(2.0 M_⊙) ≤ 1.16 R(1.4 M_⊙) − 1.1 km for neutron stars sharing one causal EoS, saturated by an analytic one-parameter family.
-
The Non-parametric Equation of State Realizes a Generalized Quark-Hadron Crossover
Non-parametric EOS construction from crust to pQCD forces a sound-speed peak and softening that realizes a generalized quark-hadron crossover in massive neutron stars.
-
Strongly Interacting Dark Matter admixed Neutron Stars
Strongly interacting dark matter described by a first-principles G2 gauge-theory equation of state can be mixed into neutron stars while remaining compatible with current observational constraints.
-
Systematic study of the morphology and length of slow stable hybrid star branches
Slow hadron-quark conversion in hybrid neutron stars creates extended stable 'waterfall' branches, reviving stiff hadronic equations of state that rapid-conversion analyses reject.
-
Is the coexistence of strange quark stars and hadronic stars favored by astrophysical data? A Bayesian analysis
Bayesian analysis of astrophysical and laboratory data favors the two-families scenario of coexisting hadronic and strange quark stars over the one-family scenario.
-
A Physics Informed Bayesian Neural Network for the Neutron Star Equation of State
A physics-informed Bayesian neural network learns neutron-star equations of state from theoretical priors and constraints, then generates posterior mass-radius and mass-tidal-deformability distributions consistent with NICER radii and 2-solar-mass limits.
-
Emulator-Assisted Nuclear DFT Inference and Its Consequences for the Structure of Neutron Stars
Emulator-assisted Bayesian inference of an extended Skyrme EDF, jointly constrained by nuclear observables, ab initio calculations, and NICER data, produces posteriors yielding consistent neutron star crust and core properties with a provided multivariate Gaussian for bulk nuclear matter parameters.
-
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.
-
Quark and hybrid stars with renormalization group improvement of NNLO perturbative QCD
RGOPT-resummed NNLO pQCD EoS for massive quarks in beta equilibrium is fitted and applied to construct pure quark stars (X=3.08-3.58) and hybrid stars (X~2-2.98) compatible with PSR J0740+6620 and GW190814.
-
Hybrid Stars with Post-Merger Rotation Profiles
Differential rotation in hybrid stars with deconfinement phase transition allows quasi-toroidal configurations with quark matter rings and leads to degeneracies in rotational profiles at mass-radius curve intersections.
-
Magnetic field dynamics in isolated neutron stars with an external dipole field
Long-term numerical-relativity runs find isolated neutron stars with an external dipole relax to a stable mixed poloidal-toroidal field with toroidal energy ≲10% after Tayler saturation.
-
Bayesian analysis of density profile of light dark matter elucidating the properties of dark matter admixed neutron stars in the presence of hyperons
Bayesian analysis finds that the likely ranges of light dark-matter fermion mass and exponential density-profile parameter in hyperon-containing neutron stars are nearly independent of the hadronic model for symmetry-energy slopes between 40 and 58 MeV, with HESS J1731-347 and GW170817 data playing,
-
Combining the Mass--Radius Posteriors of J0030+0451 Allowing for Unknown Model Systematics
A Bayesian combination of eight M-R posteriors for PSR J0030+0451 yields M = 1.46^{+0.09}_{-0.08} M_⊙, R = 12.69^{+0.64}_{-0.55} km while marginalizing over unknown model systematics.
-
Sensitivity of Neutron Star Observables to Transition Density in Hybrid Equation-of-State Models
Hybrid neutron-star equations of state remain sensitive to the low-density nucleonic model at transition densities around 2ρ₀, with model spread in radius and tidal deformability exceeding observational uncertainty by factors of ~1.8 and ~1.4.
-
Neutron star with dark matter using vector portal
Vector-portal fermionic dark matter softens or stiffens the neutron-star equation of state depending on Z' mass, producing mass-radius and tidal-deformability signatures constrained by GW170817 and NICER.
-
Tracing the Trace Anomaly of Dense Matter inside Neutron Stars
Quasi-universal relations connect the trace anomaly profile of neutron star matter to stellar compactness, moment of inertia, and tidal deformability, yielding a central value estimate of Δ_c = 0.1770^{+0.0365}_{-0.0432} for a 1.4 M_⊙ star.
-
Dark Matter Heating in Evolving Proto-Neutron Stars: A Two-Fluid Approach
Dark matter cores heat baryonic matter in evolving proto-neutron stars by deepening the gravitational potential while halos cool it, providing a diagnostic distinct from hyperons.
-
Slowly rotating condensate dark stars beyond the mean-field approximation
The Lee-Huang-Yang beyond-mean-field correction measurably reduces the dimensionless moment of inertia of slowly rotating BEC dark stars at fixed compactness while preserving the I-Love universal relation to within a few percent.
-
Hyperonic equation of state for neutron stars: A systematic Bayesian comparison of density-dependent and non-linear relativistic mean-field models
Including hyperons reduces maximum neutron-star mass by 0.05-0.10 solar masses and increases radius at 1.4 solar masses by 0.5-0.8 km across all models while keeping every equation of state consistent with the 2-solar-mass limit.
-
Impact of hyperon mixing on neutron star structure based on Skyrme-type equations of state: Systematic analysis of $\Lambda NN$ and $\Lambda\Lambda N$ three-body forces with Bayesisan inference
Systematic scan of ΛNN and ΛΛN three-body force parameters in Skyrme EDF for beta-equilibrated hyperonic matter, TOV branch classification, and Bayesian analysis with XGBoost-SHAP on NS mass-radius constraints.
-
Characterizing the quark-hadron mixed phase in compact star cores : sensitivity to nuclear saturation and quark-model parameters at finite-temperature
The quark-hadron mixed phase width in hybrid stars is mainly controlled by effective nucleon mass and symmetry energy, with temperature reducing the width and softening the EOS while strong vector repulsion is needed to match massive pulsar and NICER data.
-
A Poincar\'e-covariant study of strange quark stars
A Poincaré-covariant vector-vector contact interaction yields an equation of state for strange quark matter whose mass-radius and tidal properties match pulsar and gravitational-wave constraints for two tuned parameter sets.
-
Equation of State Extrapolation Systematics: Parametric vs. Nonparametric Inference of Neutron Star Structure
Nonparametric GP-based high-density extensions yield softer EOS posteriors with larger uncertainties than parametric PP extensions when jointly constrained by multi-messenger neutron star observations.
-
Radial oscillations of quark stars in light of current astrophysical constraints: A comparative study
Comparative numerical study of radial modes in strange quark stars using CFL, interacting, and linear causal EOS shows all satisfy current mass-radius bounds and produce 4-7 kHz fundamental frequencies.