Role of the symmetry energy on the structure of neutron stars with unified equations of state

Chamel, Nicolas; Potekhin, A. Y.; Fantina, Anthea; Ducoin, C.; Dutta, A. K.; Goriely, Stéphane; Perot, L.

doi:10.1063/1.5117811

Cited by 5 publications

(6 citation statements)

References 63 publications

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“…More specifically, (1) and (2) were from Malik et al [64] and (3), (4), and (5) from Biswas et al [65]. The rest were from (6) Zimmerman et al [88], (7) Tsang et al [66], (8) Xie and Li [67], (9) Baillot d'Etivaux et al [68], (10) Malik et al [69], (11) Lim and Holt [71], (12) Chamel et al [75], (13) Raithel and Özel [79], (14) Carson et al [89], (15) Yue et al [80], and (16) Essick et al [81]. The average of these 16 new analyses was about K sym ≈ −107 ± 88 MeV at a 68% confidence level.…”

Section: Updated Systematics Of Symmetry Energy Parameters At ρ 0 After Incorporating the Results Of Recent Analyses Of Neutron Star Obsementioning

confidence: 99%

Progress in Constraining Nuclear Symmetry Energy Using Neutron Star Observables Since GW170817

Cai²,

Wang

et al. 2021

Universe

146

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The density dependence of nuclear symmetry energy is among the most uncertain parts of the Equation of State (EOS) of dense neutron-rich nuclear matter. It is currently poorly known especially at suprasaturation densities partially because of our poor knowledge about isovector nuclear interactions at short distances. Because of its broad impacts on many interesting issues, pinning down the density dependence of nuclear symmetry energy has been a longstanding and shared goal of both astrophysics and nuclear physics. New observational data of neutron stars including their masses, radii, and tidal deformations since GW170817 have helped improve our knowledge about nuclear symmetry energy, especially at high densities. Based on various model analyses of these new data by many people in the nuclear astrophysics community, while our brief review might be incomplete and biased unintentionally, we learned in particular the following: (1) The slope parameter L of nuclear symmetry energy at saturation density ρ0 of nuclear matter from 24 new analyses of neutron star observables was about L≈57.7±19 MeV at a 68% confidence level, consistent with its fiducial value from surveys of over 50 earlier analyses of both terrestrial and astrophysical data within error bars. (2) The curvature Ksym of nuclear symmetry energy at ρ0 from 16 new analyses of neutron star observables was about Ksym≈−107±88 MeV at a 68% confidence level, in very good agreement with the systematics of earlier analyses. (3) The magnitude of nuclear symmetry energy at 2ρ0, i.e., Esym(2ρ0)≈51±13 MeV at a 68% confidence level, was extracted from nine new analyses of neutron star observables, consistent with the results from earlier analyses of heavy-ion reactions and the latest predictions of the state-of-the-art nuclear many-body theories. (4) While the available data from canonical neutron stars did not provide tight constraints on nuclear symmetry energy at densities above about 2ρ0, the lower radius boundary R2.01=12.2 km from NICER’s very recent observation of PSR J0740+6620 of mass 2.08±0.07M⊙ and radius R=12.2–16.3 km at a 68% confidence level set a tight lower limit for nuclear symmetry energy at densities above 2ρ0. (5) Bayesian inferences of nuclear symmetry energy using models encapsulating a first-order hadron–quark phase transition from observables of canonical neutron stars indicated that the phase transition shifted appreciably both L and Ksym to higher values, but with larger uncertainties compared to analyses assuming no such phase transition. (6) The high-density behavior of nuclear symmetry energy significantly affected the minimum frequency necessary to rotationally support GW190814’s secondary component of mass (2.50–2.67) M⊙ as the fastest and most massive pulsar discovered so far. Overall, thanks to the hard work of many people in the astrophysics and nuclear physics community, new data of neutron star observations since the discovery of GW170817 have significantly enriched our knowledge about the symmetry energy of dense neutron-rich nuclear matter.

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Section: Updated Systematics Of Symmetry Energy Parameters At ρ 0 After Incorporating the Results Of Recent Analyses Of Neutron Star Obsementioning

confidence: 99%

Progress in Constraining Nuclear Symmetry Energy Using Neutron Star Observables Since GW170817

Cai²,

Wang

et al. 2021

Universe

146

View full text Add to dashboard Cite

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“…It is well known that the compressibility of nuclear matter dominates the stiffness of neutron star matter therefore significantly contributes to the determination of the maximum neutron star mass M max . On the contrary, the symmetry energy has a greater influence on the determination of the neutron star radius R [63][64][65] rather than on M max . For our analysis we have used as observational inputs for our Bayesian study the multi-messenger astronomy measurements: mass measurements of PSR J0740+6620 [5] and PSR J0348+0432 [6], tidal deformability data from GW170817 [7,8], M max boundaries [9], and combined mass-radius measurements for PSR J0030+0451 [10,11].…”

Section: Discussionmentioning

confidence: 99%

Studying the parameters of the extended σ-ω model for neutron star matter

Alvarez-Castillo

Ayriyan

Barnaföldi

et al. 2020

Eur. Phys. J. Spec. Top.

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In this work we study the parameters of the extended σ-ω model for neutron star matter by a Bayesian analysis of state-of-the-art multi-messenger astronomy observations, namely mass, radius and tidal deformabilities. We have considered three parameters of the model, the Landau mass mL, the nuclear compressibility K0, and the value of the symmetry energy S0, all at saturation density n0. As a result, we are able to estimate the best values of the Landau mass of mL ≈ 0.73 GeV, whereas the values of K0 and S0 fall within already known empirical values. Furthermore, for neutron stars we find the most probable value of 13 km < R1.4 < 13.5 km and the upper mass limit of Mmax ≈ 2.2 M⊙.

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“…is the relative fraction of the proton and neutron degrees of freedom. Its value is fitted as it is described for example in reference [12], but as we pointed out in our work [1] the value of the symmetry energy plays negligible role for maximal mass stars as it is well known from references [3][4][5][6].…”

Section: The Model and The Equation Of Statementioning

confidence: 99%

“…Applying our phenomenological linear formulae we could determine precisely the Landau effective mass value, m L ≈ 780 MeV, which was consistent with our preliminary Bayesian analysis in reference [2] as well. Here we investigate the subsequent a e-mail: barnafoldi.gergely@wigner.hu parameter in the above order, the compressibility K, which certainly has less impact on the maximal mass, than the radius, R [3][4][5][6]. Using our linear fits we present the parameter domain structure, while taking mass observation data from PSR J0740+6620 [7], PSR J0348+0432 [8], and PSR J1614−2230 [9], we estimate the mean K value including the uncertainties originating from both the theory and the data.…”

Section: Introductionmentioning

confidence: 99%

Estimating compressibility from maximal-mass compact star observations

Barnaföldi

Pósfay

Szigeti

et al. 2020

Eur. Phys. J. Spec. Top.

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We investigated recent observation data of pulsar masses of PSR J0740+6620, PSR J0348+0432, and PSR J1614−2230 based on the extended σ-ω model. We assumed that these pulsars are maximal mass compact star, which suggest that the core approximation can be applied. Using the linear relations between the microscopic and macroscopic parameters of neutron stars suggested by this model, we estimated the values of the nucleon Landau mass and nuclear compressibility mL=776.0−84.9+38.5 MeV and K=242.7−28.0+57.2 MeV, respectively.

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Role of the symmetry energy on the structure of neutron stars with unified equations of state

Cited by 5 publications

References 63 publications

Progress in Constraining Nuclear Symmetry Energy Using Neutron Star Observables Since GW170817

Progress in Constraining Nuclear Symmetry Energy Using Neutron Star Observables Since GW170817

Studying the parameters of the extended σ-ω model for neutron star matter

Estimating compressibility from maximal-mass compact star observations

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