Confirming the Existence of Twin Stars in a NICER Way

Christian, Jan-Erik; Schaffner–Bielich, Jürgen

doi:10.3847/1538-4357/ac75cf

Cited by 19 publications

(13 citation statements)

References 79 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Finally, we note that, while our prior ensemble contains a large number of EoSs that admit twin stars with multiple stable branches, the mass measurements give a vanishing weight to EoSs with multiple stable branches. We note however that this finding is not in contradiction with other works (e.g., Benic et al 2015;Christian & Schaffner-Bielich 2020;Christian & Schaffner-Bielich 2022) finding twin-star solutions. These works utilize more specific EoS parameterizations including explicit strong first-order transitions, which are approximated by smooth but rapidly changing functions and have a small prior weight in our analysis.…”

Section: Resultscontrasting

confidence: 78%

Ab-initio QCD Calculations Impact the Inference of the Neutron-star-matter Equation of State

Gorda

Komoltsev

Kurkela

2023

ApJ

View full text Add to dashboard Cite

We demonstrate that ab-initio calculations in QCD at high densities offer significant and nontrivial information about the equation of state of matter in the cores of neutron stars, going beyond that which is obtainable from current astrophysical observations. We do so by extrapolating the equation of state to neutron-star densities using a Gaussian process and conditioning it sequentially with astrophysical observations and QCD input. Using our recent work, imposing the latter does not require an extrapolation to asymptotically high density. We find the QCD input to be complementary to the astrophysical observations, offering strong additional constraints at the highest densities reached in the cores of neutron stars; with the QCD input, the equation of state is no longer prior dominated at any density. The QCD input reduces the pressure and speed of sound at high densities, and it predicts that binary collisions of equal-mass neutron stars will produce a black hole with greater than 95% (68%) credence for masses M ≥ 1.38M ⊙ (M ≥ 1.25M ⊙). We provide a Python implementation of the QCD likelihood function so that it can be conveniently used within other inference setups.

show abstract

Section: Resultscontrasting

confidence: 78%

Ab-initio QCD Calculations Impact the Inference of the Neutron-star-matter Equation of State

Gorda

Komoltsev

Kurkela

2023

ApJ

View full text Add to dashboard Cite

show abstract

“…This observation is consistent with a phase transition from hadronic to quark matter, which can improve the agreement of theoretical models with the TD extracted from GW170817 event (e.g., Annala et al 2018;Paschalidis et al 2018;Most et al 2018;Tews et al 2018;Burgio et al 2018;Alvarez-Castillo et al 2019;Christian et al 2019;Montana et al 2019;Sieniawska et al 2019;Essick et al 2020;Li et al 2020a;Miao et al 2020;Li et al 2021a;Malfatti et al 2020;Rodriguez et al 2021;. Furthermore, the phase transition may lead to the emergence of new branches of stable CSs which provides a new diagnostics of phase transition in CSs through observation of twin and triplet stars, i.e., one or two hybrid stars having the same mass, but different radii from, a purely hadronic star (e.g., Alford et al 2013;Alford & Sedrakian 2017;Paschalidis et al 2018;Alvarez-Castillo et al 2019;Christian et al 2019;Montana et al 2019;Li et al 2020a;Christian & Schaffner-Bielich 2022a).…”

Section: Introductionmentioning

confidence: 94%

Relativistic hybrid stars with sequential first-order phase transitions in light of multimessenger constraints

Li¹,

Sedrakian²,

Alford³

2023

Preprint

View full text Add to dashboard Cite

In this work, we consider the properties of compact stars in which quark matter has low-and high-density phases that are separated by a first-order phase transition. Thus, unlike the commonly considered case of a single-phase transition from hadronic to quark matter, our models of hybrid stars contain sequential phase transitions from hadronic matter to low-and then to high-density quark matter phases. We extend our previous study of the parameter space of hybrid stars with a single phase transition to those with sequential phase transitions, taking into account the constraints on the mass and radius of neutron stars from the NICER experiment, the experimental inferences of the neutron skin thickness of Lead nucleus by the PREX-II experiment and constraints on the tidal deformability from the gravitational wave event GW170817. We determine the range of the masses for which both twin and triplet configurations, i.e., identical-mass stars with two and three different values of radii arise.

show abstract

“…(e.g., Paschalidis et al 2018;Montana et al 2019;Blaschke et al 2020;Li et al 2021;Christian & Schaffner-Bielich 2022;Li et al 2023a). In the second scenario, in contrast, the phase transition occurs at ρ tran /ρ sat  3.0, so that the heaviest star on the nucleonic branch has…”

Section: Hybrid Modelsmentioning

confidence: 99%

New Covariant Density Functionals of Nuclear Matter for Compact Star Simulations

Li,

Sedrakian

2023

ApJ

View full text Add to dashboard Cite

We generate three families of extended covariant density functionals of nuclear matter that have varying slope of symmetry energy and skewness at nuclear saturation density, but otherwise share the same basic parameters (symmetry energy, compressibility, saturation parameters, etc.) with the standard DDME2, DD2, and MPE functionals. Tables of the parameters of these new density functionals are given, which can be straightforwardly used in DDME2, DD2, and MPE parameterization-based codes. Furthermore, we provide tables of a large number of equations of state (81 for each family) that can be used in astrophysical simulations to assess the impact of variations of the not-well-known slope of symmetry energy and skewness of nuclear systems on the astrophysics of compact objects. We also provide tables of computed integral parameters (mass, radius, and tidal deformability) that can be used, e.g., for modeling gravitational waveforms. Finally, for the extended DDME2-based parameterization, we implement a first-order phase transition to quark matter to obtain a family of equations of state that accommodates a phase transition to quark matter. Analogous tables of the equations of state and integral parameters are provided for this case as well.

show abstract

Confirming the Existence of Twin Stars in a NICER Way

Cited by 19 publications

References 79 publications

Ab-initio QCD Calculations Impact the Inference of the Neutron-star-matter Equation of State

Ab-initio QCD Calculations Impact the Inference of the Neutron-star-matter Equation of State

Relativistic hybrid stars with sequential first-order phase transitions in light of multimessenger constraints

New Covariant Density Functionals of Nuclear Matter for Compact Star Simulations

Contact Info

Product

Resources

About