Locating ergostar models in parameter space

Tsokaros, Antonios; Ruiz, Milton; Shapiro, Stuart L.

doi:10.1103/physrevd.101.064069

Cited by 12 publications

(13 citation statements)

References 39 publications

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“…It may even belong to a third‐family branch of hybrid stars. For a discussion of EoS constraints when the companion star of GW190814 being a neutron star and not a black hole, see also Kanakis‐Pegios et al (2020); Tsokaros et al (2020). It is not possible from GW190814 alone to conclude whether the lighter companion was the lightest black hole or the heaviest neutron star observed to date.…”

Section: A Special Point For Hybrid Starsmentioning

confidence: 99%

Studying the onset of deconfinement with multi‐messenger astronomy of neutron stars

Blaschke

Cierniak

2021

Astron Nachr

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With the first multi‐messenger observation of a binary neutron star merger (GW170817), new constraints became available for masses and radii of neutron stars. We introduce a class of hybrid EoS that fulfills all these constraints and predicts a region in the mass‐radius diagram that could be populated only by hybrid neutron stars with quark matter cores. A confirmation of this conjecture would be provided when the NICER radius measurement for the high‐mass pulsar PSR J0740 + 6620 yields a radius significantly less than 11 km. Would this radius measurement yield a result in excess of 12 km, this would allow for both, a purely hadronic and a hybrid nature of this star. In the latter case, the maximum mass could reach 2.6 M⊙ so that the lighter object in the asymmetric binary merger GW190814 could have been a hybrid star. We demonstrate that this high mass can be compatible with an early onset of deconfinement for stars with masses below 1 M⊙ and the occurrence of low‐mass twin stars. In such a case, the remnant of GW170817 could be a long‐lived hypermassive pulsar.

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Section: A Special Point For Hybrid Starsmentioning

confidence: 99%

Studying the onset of deconfinement with multi‐messenger astronomy of neutron stars

Blaschke

Cierniak

2021

Astron Nachr

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“…Over the years, the numerical relativity community has developed a number of codes for computing BNS initial data in certain portions of the parameter space. Some of the best known codes are: the open source spectral code LORENE [25] with non-public extensions, e.g., [26], the Princeton group's multigrid solver [27], BAM's multigrid solver [28,29], the COCAL code [30,31], SpEC's spectral solver Spells [32,33], and the spectral code SGRID [22,[34][35][36]. Recent developments include [37,38].…”

Section: Introductionmentioning

confidence: 99%

Constructing binary neutron star initial data with high spins, high compactnesses, and high mass ratios

Tichy¹,

Rashti²,

Dietrich³

et al. 2019

Phys. Rev. D

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The construction of accurate and consistent initial data for various binary parameters is a critical ingredient for numerical relativity simulations of the compact binary coalescence. In this article, we present an upgrade of the pseudospectral SGRID code, which enables us to access even larger regions of the binary neutron star parameter space. As a proof of principle, we present a selected set of first simulations based on initial configurations computed with the new code version. In particular, we simulate two millisecond pulsars close to their breakup spin, highly compact neutron stars with masses at about 98% of the maximum supported mass of the employed equation of state, and an unequal mass systems with mass ratios even outside the range predicted by population synthesis models (q = 2.03). The discussed code extension will help us to simulate previously unexplored binary configurations. This is a necessary step to construct and test new gravitational wave approximants and to interpret upcoming binary neutron star merger observations. When we construct initial data, one has to specify various parameters, such as a rotation parameter for each star. Some of these parameters do not have direct physical meaning, which makes comparisons with other methods or models difficult. To facilitate this, we introduce simple estimates for the initial spin, momentum, mass, and center of mass of each individual star.

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“…These high theoretical limits on the maximum mass of neutron stars around ≈ 3 − 4 M are quite beyond the observational bound of pulsars around 2.2 M (Cromartie et al 2020); observations of accreting black holes, on the other hand, hinted a paucity of sources with masses below 5 M (e.g., Bailyn et al 1998;Özel et al 2010;Farr et al 2011;Kreidberg et al 2012). However, binary merger involving one or two companions with masses that fall into the so-called mass gap range (≈ 3 − 5M ) are hard to distinguish (e.g., Wyrzykowski & Mandel 2020;Tsokaros et al 2020;Abbott et al 2020).…”

Section: Tidal Deformabilitymentioning

confidence: 99%

Constraining hadron-quark phase transition parameters within the quark-mean-field model using multimessenger observations of neutron stars

Miao,

Li,

Zhu

et al. 2020

Preprint

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We extend the quark mean-field (QMF) model for nuclear matter and study the possible presence of quark matter inside the cores of neutron stars. The QMF model relates consistently the dynamics of the internal quark structure of a nucleon to the relativistic mean-fields arising in nuclear matter, and can satisfy empirical constraints from both low-density nuclear experiments and neutron star observations. The study on a first-order hadron-quark phase transition is performed, combining the QMF for the hadronic phase with "constant-speed-of-sound" parameterization for the high-density quark phase. The interplay of the nuclear symmetry energy slope parameter, L, and the dimensionless phase transition parameters (the transition density n trans /n 0 , the transition strength ∆ε/ε trans , and the sound speed squared in quark matter c 2 QM ) are then systematically explored for the hybrid star proprieties, especially the maximum mass M max and the radius and the tidal deformability of a typical 1.4M star R 1.4 . We show the strong correlation between the symmetry energy slope and the typical stellar radius, similar to that previously found for neutron stars without a phase transition. With the inclusion of phase transition, we obtain robust limits on the maximum mass (M max < 3.6M ) and the radius of 1.4M stars (R 1.49.6 km), and we find that the phase transition should not take place below ≈ 1.31 times the nuclear saturation density. We also demonstrate that future measurements of the radius and tidal deformability of ∼ 1.4M stars, as well as the mass measurement of very massive pulsars, can help reveal the presence and amount of quark matter in compact objects.

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Locating ergostar models in parameter space

Cited by 12 publications

References 39 publications

Studying the onset of deconfinement with multi‐messenger astronomy of neutron stars

Studying the onset of deconfinement with multi‐messenger astronomy of neutron stars

Constructing binary neutron star initial data with high spins, high compactnesses, and high mass ratios

Constraining hadron-quark phase transition parameters within the quark-mean-field model using multimessenger observations of neutron stars

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