Properties of rotating neutron star in density-dependent relativistic mean-field models

Riahi, R.; Kalantari, S. Z.

doi:10.1142/s0218271821500012

Cited by 6 publications

(5 citation statements)

References 76 publications

(85 reference statements)

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“…On the other hand, the possibility for GW190814's secondary as a neutron star can be accomplished by: (1) choosing/constructing stiff EOSs having a maximum mass larger than 2.5 M [76,[141][142][143][144][145][146][147][148][149][150]; (2) considering the effects of fast rotations, which can increase the maximum mass by about 20% when a star rotates at the Kepler frequency (the maximum frequency at which the gravitational attraction is still sufficient to keep matter bound to the pulsar surface) [42,43,139,140,145,[151][152][153][154][155][156][157] ; (3) considering other effects/models that can modify the maximum mass of a neutron star, such as the magnetic field [147], twin star [158], two families of compact stars [142], finite temperature [153], antikaon condensation [159], net electric charge [144], etc.…”

Section: Is Gw190814's Secondary a Superfast And Supermassive Neutron Star Or Something Else?mentioning

confidence: 99%

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

Cai²,

Wang

et al. 2021

Universe

147

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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: Is Gw190814's Secondary a Superfast And Supermassive Neutron Star Or Something Else?mentioning

confidence: 99%

“…Rather, it can be a fast pulsar collapsed to a rotating BH at some point before the merger. Riahi & Kalantari [155] calculated the maximum mass at Kepler frequency with four DDRMF EOSs. Two of them can support pulsars heavier than 2.5 M after considering rotation.…”

Section: Is Gw190814's Secondary a Superfast And Supermassive Neutron Star Or Something Else?mentioning

confidence: 99%

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

Cai²,

Wang

et al. 2021

Universe

147

View full text Add to dashboard Cite

show abstract

“…On the other hand, the possibility for GW190814's secondary as a neutron star can be accomplished by: 1) Choose/construct stiff EOSs having the maximum mass larger than 2.5 M [131][132][133][134][135][136][137][138][139][140][141] ; 2) Consider effects of fast rotations which can increases the maximum mass by about 20% when a star rotates at the Kepler frequency (the maximum frequency at which the gravitational attraction is still sufficient to keep matter bound to the pulsar surface) [35,36,129,130,136,[142][143][144][145][146][147][148]; 3) Consider other effects/models that can modify the maximum mass of neutron star, such as magnetic field [138], twin star [149], two family compact star [132], finite-temperature [144], antikaon condensation [150], or net electric charge [134], etc.…”

Section: Is Gw190814's Secondary a Superfast And Supermassive Neutron...mentioning

confidence: 99%

“…Rather, it can be a fast pulsar collapsed to a rotating BH at some point before the merger. Riahi & Kalantari [146] calculated the maximum mass at Kepler frequency with four DDRMF EOSs. Two of them can support pulsars heavier than 2.5 M after considering rotation.…”

Section: Is Gw190814's Secondary a Superfast And Supermassive Neutron...mentioning

confidence: 99%

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

Li,

Cai,

Xie

et al. 2021

Preprint

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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, to pin 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 have learned particularly: (1) The slope parameter L of nuclear symmetry energy at saturation density ρ 0 of nuclear matter from 24 new analyses of neutron star observables is about L ≈ 57.7 ± 19 MeV at 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 K sym of nuclear symmetry energy at ρ 0 from 16 new analyses of neutron star observables is about K sym ≈ −107 ± 88 MeV at 68% confidence level in very good agreement with the systematics of earlier analyses, (3) The magnitude of nuclear symmetry energy at 2ρ 0 , i.e. E sym (2ρ 0 ) ≈ 51 ± 13 MeV at 68% confidence level, has been extracted from 9 new analyses of neutron star observables consistent with 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 do not provide tight constraints on nuclear symmetry energy at densities above about 2ρ 0 , the lower radius boundary R 2.01 = 12.2 km from NICER's very recent observation of PSR J0740+6620 of mass 2.08 ± 0.07 M and radius R = 12.2 − 16.3 km at 68% confidence level sets a tight lower limit for nuclear symmetry energy at densities above 2ρ 0 , (5) Bayesian inferences of nuclear symmetry energy using models encapsulating a first-order hadron-quark phase transition from observables of canonical neutron stars indicate that the phase transition shifts appreciably both the L and K sym to higher values but with larger uncertainties compared to analyses assuming no such phase transition, (6) The high-density behavior of nuclear symmetry energy affects significantly 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 enriched significantly our knowledge about the symmetry energy of dense neutron-ric...

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“…As the mass of the secondary component of GW190814 lies in the lower region of the mass-gap (2.5M < M < 5M ), it raised the question whether it is a light black hole or a very massive NS. To understand this object, many interesting theories have been proposed recently regarding its nature as the most massive NS, lightest black hole, or fastest pulsar (Godzieba et al 2021;Most et al 2020;Tsokaros et al 2020;Fattoyev et al 2020;Lim et al 2020a;Tews et al 2021;Rather et al 2021b;Sedrakian et al 2020;Beniamini et al 2020;Biswas et al 2020;Roupas et al 2020;Zhou et al 2021;Wu et al 2021;Khadkikar et al 2021;Bombaci et al 2020;Goncalves & Lazzari 2020;Christian & Schaffner-Bielich 2021;Demircik et al 2021;Li et al 2020;Riahi & Kalantari 2021;Dhiman et al 2007;Shahrbaf et al 2020;Huang et al 2020b;Lim et al 2020b;Tan et al 2020;Gupta et al 2020;Dexheimer et al 2021).…”

Section: Introductionmentioning

confidence: 99%

Heavy Magnetic Neutron Stars

Rather,

Rahaman,

Dexheimer

et al. 2021

Preprint

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Context.Aims. We systematically study the properties of pure nucleonic and hyperonic magnetic stars using a density-dependent relativistic mean field (DD-RMF) equations of state. Methods. We explore several parameter sets and hyperon coupling schemes within the DD-RMF formalism. We focus on sets that agree with nuclear and other astrophysical data, while generating heavy neutron stars. Magnetic field effects are included in the matter equation of state and in general relativity solutions, which in addition fulfill Maxwell's equations. Results. We find that pure nucleonic matter, even without magnetic field effects, generates neutron stars that satisfy the potential GW190814 mass constraint; however, this is not the case for hyperonic matter, which instead only satisfies the more conservative 2.1 M constraint. In the presence of strong but still realistic internal magnetic fields ≈ 10 17 G, the stellar charged particle population re-leptonizes and de-hyperonizes. As a consequence, magnetic fields stiffen hyperonic equations of state and generate more massive neutron stars, which can satisfy the possible GW190814 mass constraint but present a large deformation with respect to spherical symmetry.

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Properties of rotating neutron star in density-dependent relativistic mean-field models

Cited by 6 publications

References 76 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

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

Heavy Magnetic Neutron Stars

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