Heavy Magnetic Neutron Stars

Rather, I. A.; Rahaman, Usuf; Dexheimer, V.; Usmani, A. A.; Patra, S. K.

doi:10.48550/arxiv.2104.05950

Cited by 4 publications

(4 citation statements)

References 65 publications

(80 reference statements)

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“…A major challenge for realistic but still standard neutron star EoS models is producing a large maximum mass. Reaching masses as high as that of the light component of the GW190814 event is very difficult, specially when including hyperonic degrees of freedom (without resorting to fast rotation [11,12,16,23,[129][130][131][132], or strong magnetic fields [133]). Reaching masses as high as the companion of V723 Mon would not be possible at all with most standard EoS models.…”

Section: B How To Construct the Heaviest Neutron Starsmentioning

confidence: 99%

Extreme matter meets extreme gravity: Ultraheavy neutron stars with phase transitions

et al. 2022

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The speed of sound of the matter within neutron stars may contain non-smooth structure related to first-or higher-order phase transitions. Here we investigate what are the observable consequences of structure in the speed of sound, such as bumps, spikes, step functions, plateaus, and kinks. One of the main consequences is the possibility of ultra-heavy neutron stars (with masses larger than 2.5 solar masses) and mass twins in heavy (with masses larger than 2 solar masses) and ultra-heavy neutron stars. These stars pass all observational and theoretical constraints, including those imposed by recent LIGO/Virgo gravitational-wave observations and NICER X-ray observations. We thoroughly investigate other consequences of this structure in the speed of sound to develop an understanding of how non-smooth features affect astrophysical observables, such as stellar radii, tidal deformability, moment of inertia, and Love number. Our results have important implications for future gravitational wave and X-ray observations of neutron stars and their impact in nuclear astrophysics.

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Section: B How To Construct the Heaviest Neutron Starsmentioning

confidence: 99%

Extreme matter meets extreme gravity: Ultraheavy neutron stars with phase transitions

et al. 2022

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“…A major challenge for realistic but still standard neutron star EoS models is producing a large maximum mass. Reaching masses as high as that of the light component of the GW190814 event is very difficult, specially when including hyperonic degrees of freedom (without resorting to fast rotation [11,12,16,23,[125][126][127][128], or strong magnetic fields [129]). Reaching masses as high as the companion of V723 Mon would not be possible at all with most standard EoS models.…”

Section: B How To Construct the Heaviest Neutron Starsmentioning

confidence: 99%

Extreme Matter meets Extreme Gravity: Ultra-heavy neutron stars with crossovers and first-order phase transitions

Tan,

Dore,

Dexheimer

et al. 2021

Preprint

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The speed of sound of the matter within neutron stars may contain non-smooth structure related to first-order phase transitions or crossovers. Here we investigate what are the observable consequences of structure in the speed of sound, such as bumps, spikes, step functions, plateaus, and kinks. One of the main consequences is the possibility of ultra-heavy neutron stars (with masses larger than 2.5 solar masses) and mass twins in heavy (with masses larger than 2 solar masses) and ultra-heavy neutron stars. These stars pass all observational and theoretical constraints, including those imposed by recent LIGO/Virgo gravitational-wave observations and NICER X-ray observations. We thoroughly investigate other consequences of this structure in the speed of sound to develop an understanding of how non-smooth features affect astrophysical observables, such as stellar radii, tidal deformability, moment of inertia, and Love number. Our results have important implications for future gravitational wave and X-ray observations of neutron stars and their impact in nuclear astrophysics.

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“…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%

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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Heavy Magnetic Neutron Stars

Cited by 4 publications

References 65 publications

Extreme matter meets extreme gravity: Ultraheavy neutron stars with phase transitions

Extreme matter meets extreme gravity: Ultraheavy neutron stars with phase transitions

Extreme Matter meets Extreme Gravity: Ultra-heavy neutron stars with crossovers and first-order phase transitions

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

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